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Effects of Astragaloside IV on IFN-Gamma Level and Prolonged Airway Dysfunction in a Murine Model of Chronic Asthma
Abstract
Astragaloside IV (AST) is the main active constituent of Radix Astragali, a Chinese herb traditionally used to prevent asthma attack from chronic asthma patients. Its efficacy and action mechanisms in asthma attack prevention remain nonetheless to be further explored. In this study, chronic asthma was induced exposing ovalbumin (OVA) sensitized mice to repeated OVA challenges twice every two weeks for 12 weeks. Mice were treated with AST for 4 weeks just after the final challenge. In this murine model of chronic asthma, the airway dysfunction and remodeling remained severe and was accompanied with suppression of the IFN-gamma level in the bronchoalveolar lavage fluid (BALF) even four weeks after the final challenge, indicating that the airway structural changes continued to develop even after interruption of OVA challenges. However, after AST treatment, the airway hyperresponsiveness was sharply relieved, accompanied by the reduction of collagen deposition and mucus production, meanwhile the inflammatory cells were decreased but the IFN-gamma level increased in BALF. In conclusion, AST could prevent the development of chronic asthma, thus reducing asthma attacks. Our results indicated that it should be used as a supplementary therapy on preventing asthma attacks from chronic asthma patients.
... [4] It also has been used in Chinese medicine for the treatment of liver cirrhosis and fibrosis with an excellent safety record. [5,6] Ca lycosin-7-O-β-D-glucopyranoside [ Figure 1] is a natural isoflavone, which is one of the two functional components of AR prescribed in Chinese pharmacopoeia, [3] and its hepatoprotective effect has not been reported. Bifendate is a synthetic compound derived from schizandrin C (a component of Fructus Schizandrae) that is used in treatment of various liver diseases such as chronic viral hepatitis, chemically or drug induced hepatic injury. ...
... According to the method above, the cytotoxicity of CG (5,10,20,40,60,80, 100 mg/L) and bifendate (1,10,20,30,40,50, 60 mg/L) was detected. ...
Calycosin-7-O-β-D-glucopyranoside (CG) is a natural isoflavone found in traditional Chinese medicines Astragali Radix (AR).
Calycosin-7-O-β-D-glucopyranoside, an isoflavone isolated from AR, has been found to have potent antioxidantive effects. This study was designed to investigate whether CG prevents oxidative stress induced by thioacetamide (TAA).
BRL-3A cells were pretreated with different concentrations of CG (10, 20, 40 mg/mL) for 12 h and then exposed to 0.18 mol/L TAA for 2 h. The cell viability were examined by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium assay, total antioxidant capacity, malondialdehyde (MDA) and the activity of antioxidant enzymes, including catalase, glutathione peroxidase and superoxide dismutase were determined by microplate method. Reactive oxygen species (ROS) generation was quantified by the 2',7'-dichlorofluorescin-diacetate method. Protein and mRNA expression of CYP2E1 were determined by western blotting and real-time PCR.
The cell oxidative stress was significantly increased after 2 h of TAA exposure. Pretreatment of BRL-3A cells with CG significantly increased the activities of antioxidant enzymes, scavenged ROS and reduced MDA production. CG decreased the expression of CYP2E1, and ultimately decreased TAA-induced BRL-3A cells oxidative stress.
Calycosin-7-O-β-D-glucopyranoside has a protective effect against TAA-induced oxidative stress in BRL-3A cells, and that the underlying mechanism involves in scavenging of ROS and the modulating expression of CYP2E1.
... Modern medicine has found that all types of traditional Chinese medicine and its extracts have significant therapeutic effects on asthma [24]. In recent years, animal research on astragaloside IV (AS-IV) in the prevention and treatment of chronic asthma has made progress [25]. The mechanism of AS-IV in the treatment of asthma is elucidated from the aspects of inhibiting airway inflammation and remodeling, and regulating immunity and neuroendocrine function. ...
Asthma is a common chronic respiratory disease, and its treatment is a core problem and challenge in clinical practice. Glucocorticoids (GCs) are the first-line therapy for the treatment of asthma. Local and systemic adverse reactions caused by GCs create obstacles to the treatment of asthma. Therefore, the research target is to find a new, safe, and effective therapeutic medicine at present. Natural products are an important source for treating asthma with low cost and low toxicity. Astragaloside IV (AS-IV) is an active ingredient of traditional Chinese medicine Astragalus mongholicus Bunge. Previous studies have indicated that AS-IV plays a therapeutic role in the treatment of asthma by inhibiting airway inflammation and remodeling the airway, and by regulating immunity and neuroendocrine function (Fig. 1) . It has a variety of biological characteristics such as multi-target intervention, high safety, and good curative effect. This article reviews the specific mechanism of AS-IV for the treatment of asthma to provide references for subsequent research.
... In ovarian tumor cells the Astragaloside-IV treatment may prevent the malignancy induced by M2 macrophages via inhibiting the HMGB1 (high mobility group box1)/ TLR4 signaling, suggesting its capability in treating ovarian tumors [128]. Astragaloside-IV has been demonstrated to augment IFNγ levels, enhance airway hypersensitivity, and reduce protein expression of TGFβ1 as well as thymic stromal lymphopoietin in asthma mouse model [129,130]. The inhibitory effect of astragaloside-IV on HepG2 cell proliferation has been found time and dose-dependent and related to decreased expression of onco-genes like Vav 3.1 [131]. ...
Cancer has been generally related to the possession of numerous mutations which interrupt important signaling pathways. Nevertheless, deregulated immunological signaling is considered as one of the key factors associated with the development and progression of cancer. The signaling pathways operate as modular network with different components interacting in a switch-like fashion with two proteins interplaying between each other leading to direct or indirect inhibition or stimulation of down-stream factors. Genetic, epigenetic, and transcriptomic alterations maintain the pathological conduit of different signaling pathways via affecting diverse mechanisms including cell destiny. At present, immunotherapy is one of the best therapies opted for cancer treatment. The cancer immunotherapy strategy includes harnessing the specificity and killing mechanisms of the immunological system to target and eradicate malignant cells. Targeted therapies utilizing several little molecules including Galunisertib, Astragaloside-IV, Melatonin, and Jervine capable of regulating key signaling pathways can effectively help in the management of different carcinomas.
... Bunge can effectively decrease inflammation and oxidative stress. Astragaloside IV can effectively reduce AHR, collagen deposition, mucus production and inflammatory cells while increasing IFN-γ levels in asthma models [94]. Qiu et al. found that astragaloside IV restrains OVA-induced airway inflammation by rebalancing the major regulators GATA3 and T-bet, which leads to a shift in CD4 + T cells towards Th1 cells [95]. ...
Although considerable advance has been made in diagnosing and treating, asthma is still a serious public health challenge. Traditional Chinese medicine (TCM) is an effective therapy of complementary and alternative medicine. More and more scientific evidences support the use of TCM for asthma treatment, and active ingredients from Chinese medicine plants are becoming a hot issue.
Purpose of review
To summarize the frontier knowledge on the function and underlying mechanisms of the active ingredients in asthma treatments and provide a fully integrated, reliable reference for exploring innovative treatments for asthma.
Methods
The cited literature was obtained from the PubMed and CNIK databases (up to September 2020). Experimental studies on the active ingredients of Chinese medicine and their therapeutic mechanisms were identified. The key words used in the literature retrieval were “asthma” and “traditional Chinese medicine” or “Chinese herbal medicine”. The literature on the active ingredients was then screened manually.
Results
We summarized the effect of these active ingredients on asthma, primarily including the effect through which these ingredients can regulate the immunologic equilibrium mechanism by acting on a number of signalling pathways, such as Notch, JAK-STAT-MAPK, adiponectin-iNOS-NF-κB, PGD2-CRTH2, PI3K/AKT, Keap1-Nrf2/HO-1, T-bet/Gata-3 and Foxp3-RORγt, thereby regulating the progression of asthma.
Conclusion
The active ingredients from Chinese medicine have multilevel effects on asthma by regulating the immunologic equilibrium mechanism or signalling pathways, giving them great clinical value. However, the safety and functional mechanism of these ingredients still must be further determined.
... In China, patients with COPD and PAH often turn to alternative and complementary treatments, which have been reported to be effective and safe (7). In the Chinese Pharmacopeia, Astragaloside IV (AS-IV; 3-O-β-D-xylopy ranosyl-6-O-β-D-glucopyranosyl cycloastragenol; Fig. 1) is the major biologically active compound in Huangqi (Radix Astragali Mongolici), a Chinese herbal remedy widely used for the clinical treatment of vascular diseases, such as essential hypertension and PAH (8,9). Recently, a study in vitro experiments have confirmed that AS-IV can stimulate human umbilical vein endothelial cell proliferation and the development of tube-like structures (10). ...
The Notch signaling pathway participates in pulmonary artery smooth muscle cell (PASMC) proliferation and apoptosis. Astragaloside IV (AS-IV) is an effective antiproliferative treatment for vascular diseases. The present study aimed to investigate the protective effects and mechanisms underlying AS-IV on hypoxia-induced PASMC proliferation and pulmonary vascular remodeling in pulmonary arterial hypertension (PAH) model rats. Rats were divided into the following four groups: i) normoxia; ii) hypoxia (10% O2); iii) treatment, hypoxia + intragastrical administration of AS-IV (2 mg/kg) daily for 28 days; and iv) DAPT, hypoxia + AS-IV treatment + subcutaneous administration of DAPT (10 mg/kg) three times daily. The effects of AS-IV treatment on the development of hypoxia-induced PAH, right ventricle (RV) hypertrophy and pulmonary vascular remodeling were examined. Furthermore, PASMCs were treated with 20 μmol/l AS-IV under hypoxic conditions for 48 h. To determine the effect of Notch signaling in vascular remodeling and the potential mechanisms underlying AS-IV treatment, 5 mmol/l γ-secretase inhibitor [N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT)] was used. Cell viability and apoptosis were determined by performing the MTT assay and flow cytometry, respectively. Immunohistochemistry was conducted to detect the expression of proliferating cell nuclear antigen (PCNA). Moreover, the mRNA and protein expression levels of Notch-3, Jagged-1, hes family bHLH transcription factor 5 (Hes-5) and PCNA were measured via reverse transcription-quantitative PCR and western blotting, respectively. Compared with the normoxic group, hypoxia-induced PAH model rats displayed characteristics of PAH and RV hypertrophy, whereas AS-IV treatment alleviated PAH and prevented RV hypertrophy. AS-IV also inhibited hypoxia-induced pulmonary vascular remodeling, as indicated by reduced wall thickness and increased lumen diameter of pulmonary arterioles, and decreased muscularization of distal pulmonary vasculature in hypoxia-induced PAH model rats. Compared with normoxia, hypoxia promoted PASMC proliferation in vitro, whereas AS-IV treatment inhibited hypoxia-induced PASMC proliferation by downregulating PCNA expression in vitro and in vivo. In hypoxia-treated PAH model rats and cultured PASMCs, AS-IV treatment reduced the expression levels of Jagged-1, Notch-3 and Hes-5. Furthermore, Notch signaling inhibition via DAPT significantly inhibited the pulmonary vascular remodeling effect of AS-IV in vitro and in vivo. Collectively, the results indicated that AS-IV effectively reversed hypoxia-induced pulmonary vascular remodeling and PASMC proliferation via the Notch signaling pathway. Therefore, the present study provided novel insights into the mechanism underlying the use of AS-IV for treatment of vascular diseases, such as PAH.
... sympodialis extract) had using as medicinal for asthma treatments, antiinflammation, anti-allergic (Bezerra-Santos et al. 2012) Saponins possess hypocholesterolemic and antidiabetic properties. Saponins have used for asthma treatment (Yuan et al. 2011). Terpenoid compounds known to be active against bacteria, fungi, viruses and protozoa. ...
!--[if gte mso 9]> Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Bioprospecting is an effort to create a value for biodiversity. Bioactivity identification of tree species is an important step to get high economic value from kerangas forest. Screening bioactivity of plants was conducted by ethnobotanical survey and qualitative phytochemistry compound tests. D ried leaves and barks of selected trees from kerangas forest were tested for qualitative phythochemistry compound . Result showed that parts of selected trees from kerangas forest had various phythochemistry compounds. Methanol extract of kerangas tree species have potential bioactivities. There were total of 42 plants located in heath forest, 38 species of which are used by the public as a medicine (90.48%). The number of tree species that are always available in all locations of heath forest are 10 species. There are 8 species of which are commonly used by the community as a medicine. The benefits obtained from 10 species were as analgesic, antibacterial, antidiabetic, anti-plasmodium, and vitality. One species that potentially based on the knowledge society as antidiabetic contained in heath forest is S.belangeran .
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... Specific immunotherapy (SIT) is one of the effective etiological treatments for allergic asthma, especially for IgE-mediated allergic diseases. Currently, induction of peripheral antigen specific immune tolerance is considered to be one of the main mechanisms of SIT [8,9]. Immune tolerance refers to the specific immune nonresponsiveness or low responsiveness formed by the immune system after exposure to antigens. ...
Objective: The effects and enhancement of catalpol (CP) on specific immune therapy (SIT) were investigated with an established animal model associated with bronchial asthma. Materials and methods: A total of 50 adults BALB/c mice were randomly divided into five groups with 10 mice in each group. These groups are control group, model group, CP group, SIT group and CP/SIT joint group. The mice were sensitized and challenged with OVA and Bronchoalveolar lavage fluid (BALF) and peripheral blood were obtained, the cell counts and the levels of cytokines (IL-1, IL-4, IFN-γ) in BALF were detected using ELISA methods. Results: The total number of cells in BALF of the group treated with CP/SIT joint group was significantly lower than the other experimental groups. Furthermore the eosinophils of the mice were dramatically reduced comparing the other experimental groups, the cytokines IL-1 and IL-4 display the similar tendency, but the IFN-γ concentration for the experimental groups was higher than the model group. After the therapy using CP, SIT and a combination of CP and SIT, asthma-associated inflammation was inhibited, IL-4 level was decreased and IFN-γ level was increased. In addition, the expression of TLR-4 protein in peripheral blood was detected by Western Blot method. Conclusions: In summary, CP can enhance the treating effect of SIT and the joint treatment by CP/SIT might be a potential method for clinical treatment of asthma, the mechanism is related to the inhibition of TLR-4 signaling pathway.
... Conversely, a higher IFN-γ of rats infected with multiple drug-resistant tuberculosis (TB) was observed in Prunella Vulgaris L. extracts treatment . Furthermore, Yuan et al. (2011) found that the IFN-γ concentration in the bronchoalveolar lavage fluid (BALF) of asthmatic rats increased after Astragaloside IV (AST) treatment. Therefore, it is likely that herbal extracts could increase IFN-γ concentration in animals in the case of infection or suffering from other diseases. ...
This study was conducted to investigate the effects of a mixed extract of Cortex Fraxini, Pulsatilla chinensis, and Eucommia ulmoides on growth performance, immune function, and antioxidant capacity in hemp ducks. A total of 90 one-day-old hemp ducks were randomly assigned to 5 treatments, each of which was replicated 3 times (6 ducks in each pen). The treatments were: basal control diet (CON), positive control (PC, CON + 0.5% Astragalus polysaccharides), and CON + 0.25, 0.50, and 1.00% mixed extract. The results showed that the weight of thymus gland increased (quadratic, p < 0.05) with the increasing levels of the mixed extract at 14 and 21 d, and it was greater in 0.5% mixed extract when compared with the PC (p < 0.05) at 21 d. The serum concentrations of immunoglobulin G, immunoglobulin A, and interleukin-2 increased with the increase of mixed extract in diets (quadratic, p < 0.05), and the concentration of immunoglobulin A was greater in 0.5% mixed extract when compared with the PC (p < 0.05) at 28 d. The serum concentration of MDA was decreased (quadratic, p < 0.05) at 21 d with the increase of mixed extract levels. The serum GSH-Px activity increased linearly and quadratically (p < 0.05) at 14 and 28 d, and it also increased quadratically (p < 0.05) at 21 d with the increasing levels of mixed extract. These results demonstrated that the addition of mixed extract to the diet could improve antioxidant capacity and immune function of hemp ducks.
... Astragaloside Ⅳ reduces eosinophilic airway inflammation, AHR and airway remodeling, including subepithelial fibrosis, smooth muscle hypertrophy, collagen deposition, goblet cell hyperplasia and mucus production through the sequential downregulation of total IgE, eosinophilia, IL-4, IL-13, transforming growth factor-β1 (TGF-β1) and upregulation of IFN-γ, IL-10, CD4 + CD25 + Foxp3 + regulatory T cells and Foxp3 mRNA expression. (12)(13)(14) The authors did not show that A. membranaceus produced adverse side effects. ...
Allergic asthma is thought to arise from an imbalance of immune regulation, which is characterized by the production of large quantities of IgE antibodies by B cells and a decrease of the interferon-γ/interleukin-4 (Th1/Th2) ratio. Certain immunomodulatory components and Chinese herbal formulae have been used in traditional herbal medicine for thousands of years. However, there are few studies performing evidence-based Chinese medicine (CM) research on the mechanisms and effificacy of these drugs in allergic asthma. This review aims to explore the roles of Chinese herbal formulae and herb-derived compounds in experimental research models of allergic asthma. We screened published modern CM research results on the experimental effects of Chinese herbal formulae and herb-derived bioactive compounds for allergic asthma and their possible underlying mechanisms in English language articles from the PubMed and the Google Scholar databases with the keywords allergic asthma, experimental model and Chinese herbal medicine. We found 22 Chinese herb species and 31 herb-derived anti-asthmatic compounds as well as 12 Chinese herbal formulae which showed a reduction of airway hyperresponsiveness, allergen-specifific immunoglobulin E, inflflammatory cell infifiltration and a regulation of Th1 and Th2 cytokines in vivo, in vitro and ex vivo, respectively. Chinese herbal formulae and herbderived bioactive compounds exhibit immunomodulatory, anti-inflflammatory and anti-asthma activities in different experimental models and their various mechanisms of action are being investigated in modern CM research with genomics, proteomics and metabolomics technologies, which will lead to a new era in the development of new drug discovery for allergic asthma in CM.
... Studies have indicated that ASIV is used in Chinese medicine to treat chronic kidney diseases and clinical ischemic diseases [2,3]. Growing evidence suggests that ASIV can be used in treating immune disorders [4]. Du et al. have found that ASIV enhances immune responses in mice [5]. ...
The present study was designed to investigate the effects of Astragaloside IV (ASIV) on the immune functions of RAW264.7 cells. Compared with control group, the concentrations of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α) and nitric oxide (NO) were higher in the 100 μg/mL ASIV-treatment group. The interleukin 6 (IL-6) concentration was significantly higher in the 50 and 100 μg/mL ASIV-treatment groups. The relative mRNA expression levels of IL-1β, TNF-α and inducible nitric oxide synthase (iNOS) were significantly higher in the 50 and 100 μg/mL ASIV-treatment groups. The relative mRNA expression levels of IL-6 in the 100 μg/mL ASIV-treatment group were significantly higher. In contrast, the relative mRNA expression levels of interleukin 4 (IL-4) and IL-6 markedly reduced in ASIV-treatment groups. Furthermore, ASIV promoted the secretion of CD40 and CD86 and increased the number of cells in G2/M phase. The apoptosis of RAW264.7 cells was decreased in ASIV-treatment groups. The protein levels of cyclin D1, CDK4 and CDK6, p50 and p-p65 increased in a dose-dependent manner. The ratio of p50/β-actin was significantly higher in the 50 and 100 μg/mL ASIV-treatment groups, and p-p65/p65 was significantly higher in the 25, 50 and 100 μg/mL ASIV-treatment groups. The phosphorylation levels of p38, ERK and JNK increased, and the protein expression of total p38, ERK and JNK decreased in a dose-dependent manner. These effects of ASIV were alleviated by PDTC. ASIV enhances the immune function of RAW264.7 cells by activating the NF-κB/MAPK signaling pathway.
... Astragaloside IV (AS-IV) (Fig. S1) is a cycloartane triterpene saponin and is one of the main biologically active constituents of the root of Astragalus membranaceus (Huang Qi). This root has been used as a curative agent in the treatment of a diverse array of diseases [27], including viral infection [29,33], chronic asthma [30], and lung cancer [23], and in the attenuation of myocardial fibrosis [6]. Further, A. membranaceus has been shown to display anti-scarring activity [7]. ...
Avian pathogenic Escherichia coli (APEC) induces septicemia in chickens by invading type II pneumocytes after breaching the blood–air barrier. Type II pneumocytes play an important role in maintaining the function of the blood–air barrier. Astragaloside IV has been shown in previous studies to have an anti-inflammatory effect. To explore whether astragaloside IV can inhibit APEC-induced injury in chicken type II pneumocytes, cells were infected with APEC-O78. The results showed that astragaloside IV significantly reduced cell damage in chicken type II pneumocytes induced by APEC-O78 by downregulating the production of TNF-α and IL-1β, upregulating the secretion of IL-4 and IL-10, suppressing the mRNA levels of TLR-4, TLR-5, ERK, and p38 of chicken type II pneumocytes as well as inhibiting bacterial adhesion and F-actin cytoskeleton polymerization. These results suggest that astragaloside IV may be useful in novel pharmaco-therapeutic approaches to the treatment of chicken colibacillosis.
... Meanwhile, calycosin could trigger cell apoptosis through the mitochondrial apoptotic pathway by upregulating RASD1 in human breast cancer cells, MCF-7 [31]. Astragaloside IV was one of the most common saponin compounds in RA with a variety of biological activities, including ameliorating renal [32], preventing damage to human mesangial cells [33], preventing the development of chronic asthma activities [34], attenuating allergic inflammation by regulationTh1/Th2 cytokine and enhancing CD4 + CD25 + Foxp3 T-cells in ovalbumin-induced asthma [8]. All effects of flavonoids and saponins in RA were closely related to the immune system, indicating that they contributed to immune regulation in the chemotherapy-induced immunosuppressive condition. ...
Radix Astragali (RA) is one of the commonly-used traditional Chinese medicines (TCMs) with an immunomodulatory effect confirmed in the clinic. In order to better understand the material basis for the therapeutic effects, this study was to investigate the absorbed components and their pharmacokinetic profile after oral administration of RA on cyclophosphamide-induced immunosuppression in Balb/c mice. As a result, 51 compounds in RA extract and 31 prototype compounds with nine metabolites were detected in mice plasma by the ultra-fast liquid chromatography (UFLC)-DAD-Q-TOF-MS/MS method. The pharmacokinetic parameters of five main constituents, including calycosin-7-O-glucoside, ononin, calycosin, formononetin and astragaloside IV, were obtained using HPLC-MS/MS. These results offered useful information for research on the pharmacological mechanism of RA and for its further development.
... The same saponin exhibited effects on IFN-gamma level and reduced airway dysfunction and could prevent the development of chronic asthma, thus reducing asthma attacks. It could be used as a supplementary therapy on preventing asthma attacks from chronic asthma patients (Yuan et al. 2011). ...
Saponins are widely distributed among plant kingdom and possess a wide range of pharmacological properties. Genus Astragalus is the largest in the Fabaceae family, comprising more than 2,200 species spread over the Globe. Astragalus species have been used in traditional medicine of many countries as well as in the modern one. The main use in the folk medicine of the species is due to their saponin content. The paper is focused on the above mentioned group of compounds. Details on their structure, distribution, recent information on the pharmacological properties and biotechnology of Astragalus saponins will be summarized and thoroughly discussed.
... Different classes of naturally-occurring substances have proved useful for the treatment of asthma, including theophylline, a phosphodiestarase inhibitor that is still used therapeutically. Other examples include fl avonoids , coumarins (Xiong et al., 2012), anthraquinones (Chu et al., 2012), triterpenes (Lee et al., 2012), triterpene saponins (Yuan et al., 2011), naphtoquinones (Lee et al., 2010), amongst others. However, most studies on the effects of plants and associated isolated compounds on asthma have limitations regarding focus on a single particular asthma model, use of non-standardized extracts, lack of knowledge on the active constituents or lack of knowledge on the mechanism of action involved. ...
The paper is a review of the literature on the ethnobotanical, chemical and pharmacological aspects of the species Cissampelos sympodialis Eichler, Menispermaceae, in order to assess its potential for the treatment of asthma. The aqueous infusion from the leaves of this Brazilian plant is used in the traditional medicine for the treatment of respiratory conditions, including colds, bronchitis and asthma. A multidisciplinary approach has led to the elucidation of the main chemical biomarkers and of the mechanism of action of the extract and its isolated constituents in animal models of inflammation and asthma. A comprehensive review of the literature on the species and its related chemical constituents was conducted using Pubmed, Web of Sciences, Lilacs, SciFinder, as well as conference proceedings. Retrieved literature data demonstrates that the aqueous fraction of the ethanolic extract from the leaves exerts an immunomodulatory activity in different animal models of asthma. This include an increase in the levels of anti-inflammatory cytokines, a decrease in the production of antigen-specific immunoglobulin, a decrease in mucus production and deposition in the airways, and a direct bronchodilator activity. These preclinical results clearly demonstrate the potential of this species for the treatment of asthma and points to the need for well-designed clinical trials to finally validate the traditional use of this herbal medicine.
... In a murine model of asthma, Astragaloside IV was shown to increase the level of interferon-r, improve hypersensitivity in the airways, and decrease the expression of TGF-β1 and thymic stromal lymphopoietin at the protein level. 34,35 Astragaloside IV against the proliferation of HepG2 cells was associated with a reduction in the expression of oncogenes such as Vav 3.1, and was dose-and time-dependent. 36 It can also reverse multidrug resistance in HepG2/glucosylceramide synthase (GCS) cells, which may be related to reducing expression of the GCS gene in cells. ...
To review the pharmacological effects and mechanisms of action of Astragaloside IV in Huangqi (Radix Astragali Mongolici).
Aticles focusing on Astragaloside IV in English and Chinese in databases were collected and reviewed in order to summarize the latest extraction separation, pharmacokinetics, and the pharmacological effects of astrageloside IV.
Protective effects of Astrageloside IV on the cardiovascular system, immune, digestive, nervous system were identified, and the action mechanisms were associated with regulation of the calcium balance, anti-oxydant, antiapoptosis, antivirus, and so on.
Astrageloside IV has broad application prospects, especially in cardiovascular diseases, digestive diseases, cancer and other modern high incidence, high-risk diseases, and could be developed as a medicine.
... This effect appeared due to its anti-inflammatory and antioxidant properties, including NF-í µí¼
B inactivation [43] . Other studies suggested that AST IV possesses antiinflammatory and immune regulation activity and can be used for preventing asthma attacks [44] . The previous pharmacological properties of Huangqi may at least partially explain the clinical benefits reported by the studies included in this paper. ...
Objective. To evaluate the efficacy and safety of oral Huangqi formulae for the treatment of stable COPD. Methods. The major databases were searched until September 2010 and supplemented with a manual search. Randomized controlled trials (RCTs) of oral Huangqi formulae that reported on lung function, St. George's Respiratory Questionnaire, symptom improvement and/or frequency of exacerbations were extracted by two reviewers. The Cochrane tool was used for the assessment of risk of bias in the included trials. Data were analyzed with RevMan 5.1.2 software. Results. 25 RCTs (1,661 participants) were included. Compared with conventional therapy (CT) alone, oral Huangqi formulae plus CT increased FEV1, and a similar result was found comparing Huangqi formulae with no treatment. Improvements in SGRQ total score, COPD-related symptoms and reduction of frequency of exacerbations were found in patients receiving Huangqi formulae plus CT compared to those receiving CT alone or CT plus placebo. No serious adverse events were reported. However, there were some methodological inadequacies in the included studies. Conclusions. The benefits of Huangqi formulae for stable COPD were promising, but its efficacy and safety have not been established due to methodological weakness and possible bias in the reported results. Further rigorously designed studies are warranted.
... Astragalus membranaceus water extract decreased AHR, inflammatory infiltration, and mucus secretion in the lung tissues, reduced IL-4, IL-5, and IL-13 levels and increased IFN-levels in OVA-induced animal models (Shen et al., 2008;Jin et al., 2013). Astragaloside IV treatment, the active constituent of A. membranaceus, relieved AHR, decreased the inflammatory cells but increased the IFN-level in BALF (Yuan et al., 2011). Coumarins from Peucedanum praeruptorum Dunn reduced AHR, airway eosinophilic inflammation, levels of IL-4, IL-5, and IL-13 in BALF and OVA-specific IgE in serum, and up-regulated the level of IFN-in BALF (Xiong et al., 2012c). ...
The purpose of this study was to assess the efficacy of zishentongluo (ZSTL) for the treatment of diabetic nephropathy (DN) and its related mechanisms. Forty-five patients with DN were randomized to receive either ZSTL (n = 25) or benazepril (n = 20), an angiotensin converting enzyme inhibitor, for 12 weeks. Conventional biochemical tests were performed to determine fasting blood glucose (FBG), glycated hemoglobin (HbA1c), serum creatinine (SCr), endogenous creatinine clearance rate (Ccr), total cholesterol (TC), and triglyceride (TG) levels. The urinary albumin excretion rate (UAER), and endothelin 1 (ET-1), and atrial natriuretic peptide (ANP) levels were determined with a radioimmunoassay, and vascular endothelial growth factor (VEGF) was detected using an enzyme-linked immunosorbent assay. The primary endpoint was change from the baseline to post-treatment in HbA1c. Secondary endpoints were change from baseline to post-treatment in FBG, TC, TG, UAER, SCr, Ccr, VI-C, ANP, ET-1, and VEGF. ZSTL was significantly more effective at improving the primary (i.e., HbA1c) and secondary (i.e., FBG, TC, TG, UAER, SCr, ANP, ET-1, and VEGF) outcomes than benazepril (p < 0.05). These findings suggest that ZSTL is superior to benazepril at improving the metabolic and renal functioning in patients with early-stage DN, in part, by modifying ANP, ET-1, and VEGF.
Atopic disease is a kind of abnormal immune reaction caused by tissue damage and physiological dysfunction caused by allergens. Atopic diseases involve many systems and have obvious genetic tendencies, threatening the quality of life, health, and life safety of human beings. Astragalus membranaceus is an ancient and commonly used traditional Chinese medicine widely used in allergic diseases. Astragaloside IV is one of the main active ingredients in Astragalus membranaceus and is an important index component for evaluating the quality of Astragalus membranaceus and Astragalus membranaceus preparations at present. It has good antiallergic and immunomodulatory effects. Therefore, this paper reviews and summarizes the mechanism of action, pharmacokinetics, and drug optimization research progress of astragaloside IV in the treatment of atopic diseases.
Purpose of review:
This paper purports to review recent relevant publications on the efficacy of traditional Chinese medicine in treating allergic diseases, to illustrate the pertinent mechanisms of action of TCM, and to explore the possible role of TCM in the management of allergic diseases in the foreseeable future. As TCM embodies multiple treatment modalities, only the most popular two, namely CHM (Chinese herbal medicine) and acupuncture, were discussed. Publications, especially reviews involving randomized controlled trials (RCTs) on the use of TCM on allergic diseases, published up to June 2019 were reviewed and analyzed. Papers reporting the mechanisms of action of TCM in allergic diseases were also included. Other publications in Chinese were also discussed.
Recent findings:
A startling escalation in the incidence of allergic diseases in the last several decades has posed tremendous social and financial burdens on the community. Failing to locate a cure for these chronic diseases, patients have resorted to using alternative medications of which traditional Chinese medicine (TCM) is a popular one. Thus CHM has been extensively employed for treating allergic diseases. Some investigations have been conducted to ascertain the therapeutic efficacy of CHM for allergic diseases. Although CHM has been widely deployed for treating allergic diseases, it appears from the published data that there is a dearth of conclusive evidence to establish the effectiveness of CHM for allergic diseases. It is recommended that more large- scale RCTs with prolonged durations be carried out to corroborate the efficacy of CHM for allergic diseases. On the other hand, there is ample evidence indicating that acupuncture is useful when administered alone in allergic rhinitis and asthma or when applied as an adjunct to conventional western therapy. Evidence of its utility in atopic eczema and urticaria is not definitive. It is recommended that acupuncture be integrated into the therapy of allergic rhinitis and asthma, and that CHM be used as an adjunct in the treatment of allergic diseases on an individual basis.
Astragalus membranaceus (Fisch) Bge(Huang-Qi) is a well-known herbal medicine with tonic property and has been widely used to treat cancer and other immune disorders in China and Southeast Asia for thousands of years. Accumulating evidence suggests that Huang-Qi possesses both immune-boosting and anti-inflammatory/immune-regulatory effects clinically, leaving the mechanism elusive. Recently, we discovered that Astragaloside (ASI), a major active component of Huang-Qi, is able to increase CD45 phosphatase activity. In this paper, we reviewed the recent progress of ASIs in immunoregulatory and anti-inflammatory activities, including the induction of T-cell activation, regulation of effector/regulatory T-cell balance, enhancement of CD45 phosphatase activity, inhibition of pro-inflammatory cytokine and, NF-[Formula: see text]B pathway. Finally, we hypothesized that inducing interferon-[Formula: see text] (IFN-[Formula: see text]) activity by activating CD45 protein tyrosine phosphatase (PTPase) may be involved in the protective role of ASI in two contrary immune-associated diseases. These pharmacological properties highlight the traditional uses of Astragalus and provide a new direction for subsequent research and the clinical application of this traditional herbal.
Asthma is one of the most common chronic inflammatory disorders, associated with reversible airflow obstruction, airway hyperresponsiveness, and airway remodeling. This disease has a significant impact on individuals, their families, and society. Standardized therapeutics such as inhaled corticosteroid in combination with long acting β 2 agonist have been applied for asthma control; however, complementary and alternative medicines, especially herbal medicines, are still widely used all over the world. A growing body of literature suggests that various herbals or related products might be effective in inhibiting asthmatic inflammation. In this review, we summarize recent advances about the mechanistic studies of herbal medicines on allergic airway inflammation in animal models and their potential application into clinic for asthma control.
Oxidative stress is involved in hepatic stellate cells (HSCs) activation and extracellular matrix overproduction. We previously reported the promising effects of dioscin against CCl4-induced liver fibrosis, but its effects and mechanisms on BDL- and DMN-induced liver fibrosis remain unknown. The results in the present study indicated that dioscin significantly inhibited HSCs activation and attenuated hepatic fibrosis in rats. Furthermore, dioscin markedly up-regulated the levels of sirtuin 1 (Sirt1), HO-1, GST, GCLC and GCLM via increasing the nuclear translocation of nuclear erythroid factor 2-related factor 2 (Nrf2), which in turn inhibited mitogen-activated protein kinase 14 (p38 MAPK) phosphorylation and reduced the levels of COL1A1, COL3A1, α-SMA and fibronectin. These results were further validated by knockdown of Sirt1 and Nrf2 using siRNAs silencing, and abrogation of p38 MAPK using SB-203580 (a p38 MAPK inhibitor) in HSC-T6 and LX-2 cells. Collectively, our findings confirmed the potent effects of dioscin against liver fibrosis and also provided novel insights into the mechanisms of this compound as a candidate for the prevention of liver fibrosis in the future.
Asthma is a chronic respiratory symptoms with variable airflow limitation and airway hyperresponsiveness (AHR), and causes high economic burden. Traditional Chinese medicine (TCM) has a long-lasting history of using herbal medicine in the treatment of various respiratory diseases including asthma. In the last several decades, an increasing number of herbs have been shown to be effective in the treatment of asthma in clinical trials or asthmatic inflammation in animal models. Literature about the effects of TCM on the immune system were searched in electronic databases such as PubMed, Google Scholar and Scopus from 2000 to 2014. 'TCM' and 'asthma' were used as keywords for the searches. Over 400 literatures were searched and the literatures about the immune system were selected and reviewed. We only reviewed literatures published in English. Accumulating evidence suggests that TCM can directly inhibit the activation and migration of inflammatory cells, regulate the balance of Th1/Th2 responses, and suppress allergic hyperreactivity through inducing regulatory T cells or attenuating the function of dendritic cells (DCs). These studies provided useful information to facilitate the use of TCM to treat asthma. This review was conducted to classify the findings based on their possible mechanisms of action reported.
Ethnopharmacological relevance:
Bu-Shen-Yi-Qi formulae (BSYQF) are frequently used in the treatment of chronic inflammatory diseases in the respiratory system in traditional Chinese medicine (TCM). However, the regulatory effect of BSYQF on T helper 17 (Th17) and regulatory T (Treg) cells in murine ovalbumin (OVA) asthma model remains poorly understood. In the present study, we sought to determine the effect of high-performance liquid chromatography/mass spectrometry (HPLC/MS) standardized BSYQF on chronic airway inflammation and Th17/Treg imbalance in the murine OVA asthma model.
Materials and methods:
The murine asthma model was induced by OVA sensitization and challenge and BSYQF was oral administrated. 24h after last OVA exposure, airway hyperresponsiveness (AHR) to methacholine (Mch) was assessed, and inflammatory cell counts and classification in bronchoalveolar lavage fluid (BALF) were analysed. Histopathological evaluation of the lung tissue was performed by hematoxylin and eosin (H&E) and periodic acid-Schiff (PAS) staining. Th17 and Treg associated cytokine levels in serum and BALF as well as transcription factors expression in the lung tissue were measured by ELISA, Bio-Plex and western blot assay. We also analysed the CD4(+)RORγt(+) and CD4(+)Foxp3(+) T cells in BALF and spleen by flow cytometric analysis.
Results:
Our results demonstrated that oral administration of BSYQF inhibited the markedly increased AHR and lung inflammation (p<0.05), resulted in a dramatic reduction in total inflammatory cells as well as neutrophils (Neu), lymphocytes (Lym), monocytes (Mon), eosinophils (Eos) and basophils (Bas) of OVA-induced asthmatic mice (p<0.05). Furthermore, BSYQF treatment caused a distinct reduction in IL-6, IL-10 and IL-17A levels in serum (p<0.05), and induced a significant improvement in IL-6 and IL-10 as well as a marked decrease in TGF-β1 and IL-17A levels in BALF of OVA-induced asthmatic mice (p<0.05). Mice in BSYQF treated groups also had decreased RORγt and increased Foxp3 expression in the lung tissue (p<0.05). Flow cytometry analysis revealed that CD4(+)RORγt(+) T cells elevated markedly and CD4(+)Foxp3(+) T cells decreased prominently in BALF and spleen in murine OVA asthma model (p<0.05), and BSYQF and DEX treatment lead to an obvious reduction in CD4(+)RORγt(+) T cells in BALF (p<0.05) but not in spleen. BSYQF and DEX treatment resulted in an obvious elevation in CD4(+)Foxp3(+) T cells in BALF and spleen (p<0.05).
Conclusions:
Collectively, these results demonstrated that BSYQF could suppress chronic airway inflammation and regulate Th17/Treg imbalance by inhibition of Th17 and enhancement of Treg functions in the murine OVA asthma model, which may help to elucidate the underlying regulatory mode of BSYQF on asthma treatment.
Bronchial asthma is characterized by chronic lung inflammation, airway hyperresponsiveness, and airway remodelling. Astragaloside IV (3-O-β-D-xylopyranosyl-6-O-β-D-glucopyranosyl-cycloastragenol, AST), the primary pure saponin isolated from the root of Astragalus membranaceus, is an effective compound with distinct pharmacological effects including anti-inflammation, immunoregulation, and antifibrosis. However, the effect of AST on asthma remains unclear. In the present study, in the murine model of asthma, the airway hyperresponsiveness was relieved after treatment with AST, accompanied by a reduction of inflammatory cells. In addition, the levels of IL-4 and IL-5 decreased, while the IFN-γ level increased, in bronchoalveolar lavage fluid. The compound also significantly inhibited the synthesis of GATA-3-encoding mRNA and protein in addition to increasing the synthesis of T-bet-encoding mRNA and protein in both lung tissues and CD4+ T cells. Our findings indicate that AST treatment inhibits ovalbumin-induced airway inflammation by modulating the key master switches GATA-3 and T-bet, which results in committing T helper cells to a Th1 phenotype. © 2014 S. Karger AG, Basel.
Bu-Shen-Yi-Qi-Tang (BSYQT) which is prescribed on the basis of clinical experience is commonly used in clinic of traditional Chinese medicine (TCM) for asthma treatment. The components of BSYQT include Radix Astragali (RA), Herba Epimedii (HE) and Radix Rehmanniae (RR). The aim of this study was to screen extracts of BSYQT with best anti-inflammatory activity in asthmatic mice, and separate and identify the chemical compounds in them. Our results suggested that 60% ethanol extract of herbs (H60) and granules (G60) of BSYQT were the two extracts with best anti-inflammatory activity and effects of H60 were a little better than that of G60. High-performance liquid chromatography coupled to electrospray ionization and quadrupole time-of-flight mass spectrometry (HPLC–ESI-Q-TOF-MS/MS) analysis of the major chemical compounds of H60 and G60 revealed that 56 and 42 peaks were identified separately in H60 and G60. Further analysis revealed that 38 compounds were identified shared by H60 and G60, and 18 compounds were only in H60. There were 25 compounds in HE, 6 compounds in RR and 7 compounds in RA in the 38 compounds shared by G60 and H60. These 38 chemical components were tentatively considered the material basis of the anti-inflammatory activity of G60 and H60. The differences in the amount of the 38 chemical components as well as the 18 chemical components only in H60 were tentatively considered responsible for the activity differences between H60 and G60. In conclusion, these results suggested that extracts of BSYQT had inhibitory effects on airway inflammation in asthmatic mice, and H60 and G60 demonstrated the best anti-inflammatory activity. The 38 chemical compounds shared by H60 and G60 were responsible for their anti-inflammatory activity in asthmatic mice, and the differences in chemical compounds contents and amounts between H60 and G60 were responsible for this activity differences. This work would provide support for further pharmacodynamic material basis study of BSYQT.
Astragaloside IV (AS-IV) is one of the main active constituents of Astragalus membranaceus, which has various actions on the cardiovascular system. However, its electrophysiological mechanisms are not clear. In the present study, we investigated the effects of AS-IV on action potentials and membrane currents using the whole-cell patch clamp technique in isolated guinea-pig ventricular myocytes. AS-IV prolonged the action potential duration (APD) at all three tested concentrations. The peak effect was achieved with 1×10(-6) m, at which concentration AS-IV significantly prolonged the APD at 95% repolarization from 313.1±38.9 to 785.3±83.7 ms. AS-IV at 1×10(-6) m also enhanced the inward rectifier K(+) currents (IK1) and inhibited the delayed rectifier K(+) currents (IK). AS-IV (1×10(-6) m) strongly depressed the peak of voltage-dependent Ca(2+) channel current (ICaL) from -607.3±37.5 to -321.1±38.3 pA. However, AS-IV was not found to affect the Na(+) currents. Taken together, AS-IV prolonged APD of guinea-pig ventricular myocytes, which might be explained by its inhibition of IK. AS-IV also influences Ca(2+) signaling through suppressing ICaL.
Oxidative stress is involved in hepatic fibrogenesis. Activation of hepatic stellate cells (HSCs), the key effectors in hepatic fibrogenesis, is characterized by overproduction of extracellular matrix. Astragaloside IV, the active component of Astragali Radix, has antioxidant properties and antifibrotic potential in renal fibrosis. Little is known about the role of Astragaloside IV in liver and its involvement in hepatic fibrosis. This study aims at evaluating the antifibrotic potential of Astragaloside IV and to characterize involved signal transduction pathways in culture-activated HSCs. Our results showed that Astragaloside IV attenuates oxidative stress in culture-activated HSC demonstrated by scavenging reactive oxygen species and reducing lipid peroxidation, and elevates the level of cellular glutathione by stimulating gene expression of Nrf2. Depletion of cellular glutathione by buthionine sulfoximine or abrogation of p38 MAPK by SB-203580 evidently eliminates the inhibitory effects of Astragaloside IV on genes relevant to HSC activation. These results demonstrate that Astragaloside IV inhibits HSC activation by inhibiting generation of oxidative stress and associated p38 MAPK activation, and provide novel insights into the mechanisms of Astragaloside IV as an antifibrogenic candidate in the prevention and treatment of liver fibrosis.
Astragalus membranaceus (AM), a traditional Chinese medicinal herb, has been widely used for centuries to treat asthma in China. Previous studies demonstrated that AM had inhibitory effects on airway hyperresponsiveness, inflammation and airway remodeling in murine models of asthma. However, it remained unclear whether the beneficial effects of AM on asthma were associated with CD4(+)CD25(+)Foxp3(+) Treg cells; this issue is the focus of the present work. An asthma model was established in Sprague-Dawley (SD) rats that were sensitized and challenged with ovalbumin. Bronchoalveolar lavage fluid (BALF) was assessed for inflammatory cell counts and cytokine levels. Airway hyperresponsiveness was detected by direct airway resistance analysis. Lung tissues were examined for cell infiltration, mucus hypersecretion and airway remodeling. CD4(+)CD25(+)Foxp3(+) Treg cells in the BALF and Foxp3 mRNA expression in lung tissues were examined. The oral administration of AM significantly reduced airway hyperresponsiveness to aerosolized methacholine and inhibited eosinophil counts and reduced IL-4, IL-5 and IL-13 levels and increased INF-γ levels in the BALF. Histological studies showed that AM markedly decreased inflammatory infiltration, mucus secretion and collagen deposition in the lung tissues. Notably, AM significantly increased population of CD4(+)CD25(+)Foxp3(+) Treg cells and promoted Foxp3(+) mRNA expression in a rat model of asthma. Together, these results suggest that the antiasthmatic effects of AM are at least partially associated with CD4(+)CD25(+)Foxp3(+) Tregs.
Astragaloside IV (AS-IV) has been noted for its reduction of eosinophilic airway inflammation in a murine model of chronic asthma. To gain a better understanding of the mechanisms involved in this anti-inflammatory phenomenon, the effect of AS-IV on human blood eosinophils was studied in vitro. Eosinophils were isolated from the blood of patients with mild atopic asthma, preincubated with AS-IV for 1 h and stimulated in the presence or absence of the house dust mite allergen Dermatophagoides pteronyssinus (Der p) 1 for 4 h. The survival of the eosinophils at 48 h was investigated using trypan blue and the surface expression of CC chemokine receptor 3 (CCR3) and intercellular adhesion molecule-1 (ICAM-1) by the eosinophils was analyzed using flow cytometry. The secretion of cytokines in the supernatants and the chemotaxis of the eosinophils were measured by ELISA and the transwell system, respectively. Der p 1 was found to prolong the survival of the eosinophils. Similarly, the expression of CCR3 and ICAM-1, secretion of interleukin (IL)-1β, IL-5, tumor necrosis factor (TNF)-α and the granulocyte macrophage colony stimulating factor (GM-CSF) and transmigration of the eosinophils were increased in the presence of Der p 1. However, these inductive effects on the eosinophils were significantly inhibited by AS-IV (50 µg/ml). These findings suggest that AS-IV modulates eosinophil activation and trafficking in response to Der p 1 and may therefore be a useful therapeutic option in eosinophilic asthma.
Summary CD4 T helper (Th) type 1 and Th2 cells have been identified in the airways of asthmatic pa- tients. Th2 cells are believed to contribute to pathogenesis of the disease, but the role of Th1 cells is not well defined. In a mouse model, we previously reported that transferred T cell re- ceptor-transgenic Th2 cells activated in the respiratory tract led to airway inflammation with many of the pathologic features of asthma, including airway eosinophilia and mucus produc- tion. Th1 cells caused inflammation with none of the pathology associated with asthma. In this report, we investigate the role of Th1 cells in regulating airway inflammation. When Th1 and Th2 cells are transferred together into recipient mice, there is a marked reduction in airway eosinophilia and mucus staining. To address the precise role of Th1 cells, we asked (i), Are Th2-induced responses inhibited by interferon (IFN)- g ? and (ii) Can Th1 cells induce eosino- philia and mucus in the absence of IFN- g ? In IFN- g receptor 2 / 2 recipient mice exposed to in- haled antigen, the inhibitory effects of Th1 cells on both airway eosinophilia and mucus pro- duction were abolished. In the absence of IFN- g receptor signaling, Th1 cells induced mucus but not eosinophilia. Thus, we have identified new regulatory pathways for mucus production; mucus can be induced by Th2 and non-Th2 inflammatory responses in the lung, both of which are inhibited by IFN- g . The blockade of eosinophilia and mucus production by IFN- g likely occurs through different inhibitory pathways that are activated downstream of Th2 cyto- kine secretion and require IFN- g signaling in tissue of recipient mice.
Astragaloside IV, a new cycloartane-type triterpene glycoside extract of Astragalus membranaceus Bunge, has been identified for its potent immunoregulatory, antiinflammatory, and antifibrotic actions. Here we investigated whether astragaloside IV could suppress the progression of airway inflammation, airway hyperresponsiveness, and airway remodeling in a murine model of chronic asthma. BALB/c mice sensitized to ovalbumin (OVA) were chronically challenged with aerosolized OVA for 8weeks. Astragaloside IV was orally administered at a dose of 50mgkg¹day¹ during each OVA challenge. Astragaloside IV treatment resulted in significant reduction of eosinophilic airway inflammation, airway hyperresponsiveness, interleukin (IL)-4 and IL-13 levels in bronchoalveolar lavage fluid, and total immunoglobulin E levels in serum. Furthermore, astragaloside IV treatment markedly inhibited airway remodeling, including subepithelial fibrosis, smooth muscle hypertrophy, and goblet cell hyperplasia. In addition, the expression of transforming growth factor-1 in the lung was also reduced by astragaloside IV. These data indicate that astragaloside IV may mitigate the development of characteristic features in chronic experimental asthma.
Mycobacterium bovis Bacillus Calmette-Guerin (BCG) has been shown to down-regulate experimental allergic asthma, a finding that reinforced the hygiene hypothesis. We have previously found that recombinant BCG (rBCG) strain that express the genetically detoxified S1 subunit of pertussis toxin (rBCG-S1PT) exerts an adjuvant effect that enhances Th1 responses against BCG proteins. Here we investigated the effect of this rBCG-S1PT on the classical ovalbumin-induced mouse model of allergic lung disease. We found that rBCG-S1PT was more effective than wild-type BCG in preventing Th2-mediated allergic immune responses. The inhibition of allergic lung disease was not associated with increased concentration of suppressive cytokines or with an increased number of pulmonary regulatory T cells but was positively correlated with the increase in IFN-gamma-producing T cells and T-bet expression in the lung. In addition, an IL-12-dependent mechanism appeared to be important to the inhibition of lung allergic disease. The inhibition of allergic inflammation was found to be restricted to the lung because when allergen challenge was given by the intraperitoneal route, rBCG-S1PT administration failed to inhibit peritoneal allergic inflammation and type 2 cytokine production. Our work offers a nonclassical interpretation for the hygiene hypothesis indicating that attenuation of lung allergy by rBCG could be due to the enhancement of local lung Th1 immunity induced by rBCG-S1PT. Moreover, it highlights the possible use of rBCG strains as multipurpose immunomodulators by inducing specific immunity against microbial products while protecting against allergic asthma.
Atrial natriuretic peptide (ANP) and its receptor, NPRA, have been extensively studied in terms of cardiovascular effects. We have found that the ANP-NPRA signaling pathway is also involved in airway allergic inflammation and asthma. ANP, a C-terminal peptide (amino acid 99-126) of pro-atrial natriuretic factor (proANF) and a recombinant peptide, NP73-102 (amino acid 73-102 of proANF) have been reported to induce bronchoprotective effects in a mouse model of allergic asthma. In this report, we evaluated the effects of vessel dilator (VD), another N-terminal natriuretic peptide covering amino acids 31-67 of proANF, on acute lung inflammation in a mouse model of allergic asthma.
A549 cells were transfected with pVD or the pVAX1 control plasmid and cells were collected 24 hrs after transfection to analyze the effect of VD on inactivation of the extracellular-signal regulated receptor kinase (ERK1/2) through western blot. Luciferase assay, western blot and RT-PCR were also performed to analyze the effect of VD on NPRA expression. For determination of VD's attenuation of lung inflammation, BALB/c mice were sensitized and challenged with ovalbumin and then treated intranasally with chitosan nanoparticles containing pVD. Parameters of airway inflammation, such as airway hyperreactivity, proinflammatory cytokine levels, eosinophil recruitment and lung histopathology were compared with control mice receiving nanoparticles containing pVAX1 control plasmid.
pVD nanoparticles inactivated ERK1/2 and downregulated NPRA expression in vitro, and intranasal treatment with pVD nanoparticles protected mice from airway inflammation.
VD's modulation of airway inflammation may result from its inactivation of ERK1/2 and downregulation of NPRA expression. Chitosan nanoparticles containing pVD may be therapeutically effective in preventing allergic airway inflammation.
Using an allergen-induced airway inflammation model, we show that an injection of alpha-galactosylceramide (alpha-GalCer), a ligand for invariant NK T (iNKT) cells, induced IL-27 and that this process is essential for the attenuation of the Th2 response. After the systemic administration of alpha-GalCer into the mice primed with OVA in alum, Th2 cytokine production of OVA-primed CD4(+) T cells in their lymph nodes, IgG1 and IgE Ab formation, and infiltration of eosinophils in bronchoalveolar lavage after the OVA challenge were suppressed. Systemic administration of rIFN-gamma into OVA-primed mice could not reproduce these effects of alpha-GalCer. IL-27p28 was detected both in the culture supernatant of alpha-GalCer-stimulated spleen cells and in the serum of the alpha-GalCer-treated mice, but not in the iNKT cell-deficient mice. Splenic iNKT cells produced IL-27p28 in the culture supernatant upon stimulation with PMA plus ionomycin, although the transcript of IL-27p28 in the iNKT cells was constitutively expressed regardless of the stimulation. By contrast, the transcript of IL-27EBI3 was induced in the iNKT cells upon stimulation with PMA plus ionomycin in vitro and with alpha-GalCer treatment in vivo, suggesting that IL-27 (p28/EBI3) could be produced by iNKT cells in an activation-dependent manner. Although repeated injections of rIL-27 did not substitute for the effects of a single injection of alpha-GalCer, administration of rIL-27 along with rIFN-gamma reproduced in vivo effects of the alpha-GalCer injection. These data indicate that production of both IL-27 and IFN-gamma by the alpha-GalCer treatment is responsible for suppression of the Th2 response and allergic inflammation.
The biologically active form of transforming growth factor-beta1 (TGF-beta1) plays a key role in the development of lung fibrosis. CD36 is involved in the transformation of latent TGF-beta1 (L-TGF-beta1) to active TGF-beta1. To clarify the role of CD36 in the development of silica-induced lung fibrosis, a rat silicosis model was used to observe both the inhibition of L-TGF-beta1 activation and the antifibrotic effect obtained by lentiviral vector silencing of CD36 expression.
The rat silicosis model was induced by intratracheal injection of 10 mg silica per rat and CD36 expression was silenced by administration of a lentiviral vector (Lv-shCD36). The inhibition of L-TGF-beta1 activation was examined using a CCL-64 mink lung epithelial growth inhibition assay, while determination of hydroxyproline content along with pathological and immunohistochemical examinations were used for observation of the inhibition of silica-induced lung fibrosis.
The lentiviral vector (Lv-shCD36) silenced expression of CD36 in alveolar macrophages (AMs) obtained from bronchoalveolar lavage fluid (BALF) and the activation of L-TGF-beta1 in the BALF was inhibited by Lv-shCD36. The hydroxyproline content of silica+Lv-shCD36 treated groups was significantly lower than in other experimental groups. The degree of fibrosis in the silica+Lv-shCD36-treated groups was less than observed in other experimental groups. The expression of collagen I and III in the silica+Lv-shCD36-treated group was significantly lower than in the other experimental groups.
These results indicate that silencing expression of CD36 can result in the inhibition of L-TGF-beta1 activation in a rat silicosis model, thus further preventing the development of silica-induced lung fibrosis.
Astragaloside IV (ASI) in Radix Astragali is believed to be the active component in treating heart failure. The present study aims to examine the effects of ASI on cardiovascular parameters in long-term heart failure in rats.
Using echocardiographic and haemodynamic measurements, we studied the effects of ASI on congestive heart failure (CHF) induced by ligation of the left coronary artery in rats.
ASI (0.1, 0.3 and 1.0 mg/kg/day) attenuated the decline of fractional shortening (FS). The peak derivatives of the left ventricle (LV) pressure (dp/dt) in ASI-treated groups significantly increased. Both LV internal diameters in diastole (LVIDd) and in systole (LVIDs) decreased significantly after ASI treatment (0.3 and 1.0 mg/kg/day). ASI (1.0 mg/kg/day) attenuated the decrease of LV systolic pressure (LVSP). ASI treatment inhibited compensatory hypertrophy of myocardial cells and lowered the number of apoptotic myocytes.
ASI improved cardiac functions as measured by cardiovascular parameters.
Astragaloside IV (AST‐IV) is purified from a natural plant product. Previous studies have shown that AST‐IV has anti‐oxidant activity. In the present study, we investigated the effect and mechanism of action AST‐IV on rat cardiomyocytes subjected to hypoxic conditions (up to 12 h).
Cardiomyocytes were prepared from neonatal rats and cultured under normoxic or hypoxic conditions in the absence or presence of AST‐IV (12.5, 25 or 50 µg/mL). Cell viability, malondialdehyde (MDA) levels, activity and expression of superoxide dismutase (SOD)‐1 (mRNA and protein levels determined by reverse transcription–polymerase chain reaction and western blotting, respectively) and reactive oxygen species (ROS; determined by 2′,7′‐dichlorodihydrofluorescein diacetate) were investigated under these culture conditions. Intracellular localization of AST‐IV was tested using fluorescein isothiocyanate‐labelled AST‐IV.
Hypoxic culture reduced the viability of cardiomyocytes, which was improved following treatment with 25 or 50 µg/mL AST‐IV. Under hypoxic conditions, MDA levels were double those under control conditions. Astragaloside IV (25 and 50 µg/mL) dose‐dependently reduced the increase in MDA seen in hypoxic cardiomyocytes.
Fluorescein isothiocyanate‐labelled AST‐IV entered cardiomyocytes and was localized mainly within the cytoplasm.
Under hypoxic conditions, SOD‐1 activity was decreased, but mRNA and protein expression increased, compared with normoxia. Following treatment with 25 µg/mL AST‐IV, SOD‐1 activity and expression were increased under both normoxic and hypoxic conditions. The ROS scavenging effect of AST‐IV was abolished in the presence of the SOD inhibitor sodium diethyl dithiocarbamate (25 µmol/L).
These in vitro results show that AST‐IV protects cardiomyocytes from oxidative stress‐mediated injury under hypoxic conditions. A major part of this action is achieved by upregulation of SOD‐1 content and activity within the cell cytoplasm.
We studied the effects of an anti-interleukin (IL)-5 monoclonal antibody (TRFK-5) or dexamethasone (DEX) to reverse already established airway hyperresponsiveness (AHR) and tissue eosinophilia in a Schistosoma mansoni antigen-sensitized and airway-challenged mouse model of chronic asthma. In this model at 4 d after antigen challenge there is dramatic bronchoalveolar lavage fluid (BAL) eosinophilia, AHR to intravenous methacholine (MCh), and histologic evidence of peribronchial eosinophilic infiltration and mucoid cell hyperplasia. These changes persist for up to 2 wk after antigen challenge. Treatment with DEX from Days 4 through 10 significantly reduced established airway eosinophilia compared with animals sham-treated with saline from Days 4 -10 (120 +/- 29 eosinophils/microl BAL for DEX-treated mice versus 382 +/- 60 eosinophils/microl BAL for sham-treated animals, p < 0.01). DEX-treated mice also had dramatically reduced mucoid cell hyperplasia, and airway responsiveness returned to normal. In contrast, TRFK-5 given during the same time period reduced airway eosinophilia (86 +/- 32 eosinophils/microl BAL versus 382 +/- 60 eosinophils/microl BAL, p < 0.01) but did not reduce goblet cell hyperplasia or reverse already established AHR. Treatment with DEX but not TRFK-5 also inhibited interferon gamma (IFN-gamma) content of BAL fluid (0.49 +/- 0.09 ng/ml BAL fluid for DEX versus 1.50 +/- 0.24 ng/ml BAL fluid and 1.36 +/- 0.13 ng/ml BAL fluid for TRFK-5 and sham-treated mice, respectively, both p < 0.001 versus DEX). Thus, treatment with DEX reduces established eosinophilic airway inflammation and AHR in S. mansoni-sensitized and airway-challenged mice but treatment with TRFK-5 reversed established eosinophilia without ameliorating established AHR. Together, these data suggest that once airway inflammation develops, neutralizing the effects of IL-5 or reducing eosinophilia alone may not result in inhibiting established AHR in atopic asthma.
In this investigation, we have examined the integrated relationship between IL-13, IL-4, and IL-5 for the development of airways hyperreactivity (AHR) in a model of asthma in BALB/c mice. Sensitization and aeroallergen challenge of both wild-type (WT) and IL-13 gene-targeted (IL-13-/-) mice induced allergic disease that was characterized by pulmonary eosinophilia and AHR to beta-methacholine. Although these responses in IL-13-/- mice were heightened compared with WT, they could be reduced to the level in nonallergic mice by the concomitant neutralization of IL-4. Mice in which both IL-4 and IL-13 were depleted displayed a marked reduction in tissue eosinophils, despite the development of a blood eosinophilia. Similar neutralization of IL-4 in WT mice only partially reduced AHR with no effect on tissue eosinophilia. In addition, neutralization of IL-5 in IL-13-/- mice, but not in WT mice, inhibited AHR, suggesting that tissue eosinophilia is linked to the mechanism underlying AHR only in the absence of IL-13. Additionally, mucus hypersecretion was attenuated in IL-13-/- mice, despite the persistence of AHR. Taken together, our data suggest both a modulatory role for IL-13 during sensitization and a proinflammatory role during aeroallergen challenge. The latter process appears redundant with respect to IL-4.
The mechanisms underlying airway hyperresponsiveness remain unclear, although airway inflammation and remodeling are likely important contributing factors. We hypothesized that airway physiology would differ between mice subjected to brief or chronic allergen exposure, and that these differences would be associated with characteristic inflammatory markers and indices of airway remodeling. BALB/c mice were sensitized to ovalbumin and studied at several time points following brief or chronic allergen challenge protocols. By measuring airway responses to methacholine, we demonstrated increases in maximal inducible bronchoconstriction that persisted for 8 wk following either brief or chronic allergen challenge; we also observed increases in airway reactivity, although it was only in chronically challenged mice that these changes persisted beyond the resolution of allergen-induced inflammation. Using airway morphometry, we further demonstrated that increases in maximal bronchoconstriction were associated with increases in airway contractile tissue in both models, and that chronic, but not brief, allergen challenge resulted in subepithelial fibrosis. Our observations that different aspects of sustained airway dysfunction and remodeling persist beyond the resolution of acute inflammatory events support the concept that remodeling occurs as a consequence of allergic airway inflammation, and that these structural changes contribute independently to the persistence of airway hyperresponsiveness.
The regulated expression of adhesion molecules on the surface of endothelial cells is a key process in the pathogenesis of inflammation. The saponin astragaloside IV (AS-IV), a 3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosylcycloastragenol purified from the Chinese medical herb Astragalus membranaceus (Fisch) Bge. has been shown to have anti-inflammatory effects in vivo. In this study we have investigated the effect of AS-IV on cytokine-and LPS-stimulated expression of adhesion molecules in and leukocyte adhesion to endothelial cells. We have demonstrated that AS-IV significantly reduced the adhesion promoting activity of LPS-stimulated HUVECs for polymorph-nuclear leukocytes (PMNs) and the monocytic cell line THP-1. Furthermore, by using specific cell ELISAs we could show that AS-IV decreased the LPS-induced expression of E-selectin and VCAM-1 on the surface of HUVECs in a dose and time dependent manner, whereas the expression of ICAM-1 was not affected by AS-IV. AS-IV also inhibits TNFalpha-induced VCAM-1 expression. The saponin octyl-D-glucopyranoside had no effect on the LPS-induced expression of E-selectin and VCAM-1 excluding an unspecific detergent-like effect of AS-IV. Moreover, AS-IV significantly inhibited LPS- and TNFalpha-induced specific mRNA levels for E-selectin and VCAM-1. Finally, we could show that AS-IV completely abolished LPS- and TNFalpha-induced nuclear translocation of NF-kappaB and NF-kappaB DNA binding activity in endothelial cells. We conclude that the ability of AS-IV to inhibit the NF-kappaB pathway might be one under-lying mechanism contributing to its anti-inflammatory potential in vivo.
This investigation evaluated the gastroprotective activity of Astragaloside IV, a cycloartane-type triterpene glycoside isolated from Astragalus zahlbruckneri. Gastric mucosal damage was induced in rats by intragastric ethanol (1 mL/rat). Rats treated orally with Astragaloside IV suspended in Tween 80 at 3, 10 and 30 mg kg(-1), showed 15, 37 and 52% gastroprotection, respectively. The gastroprotection observed at 30 mg kg(-1) for this compound was attenuated in rats pretreated with N(G)-nitro-L arginine methyl ester (70 mg kg(-1), i.p), a nitric oxide (NO)-synthase inhibitor, suggesting that the gastroprotective mechanism of this glycoside involves, at least in part, the participation of NO. The gastroprotective effect of Astragaloside IV was not affected by the inhibition of prostaglandin synthesis with indometacin (10 mg kg(-1), s.c.) nor by the block of endogenous sulfhydryls with N-ethylmaleimide (NEM, 10 mg kg(-1), s.c.). Carbenoxolone was used as a gastroprotective model drug and showed a dose-dependent gastroprotective effect (25, 43 and 88% of gastroprotection, at 3, 10 and 30 mg kg(-1), respectively). The partial participation of prostaglandins, sulfhydryls and NO was observed in the gastroprotective mechanism of carbenoxolone.
Asthma is a chronic inflammatory disorder of the airways driven by T cell activation. Th2 cells and their cytokines are thought to play a role in the pathophysiology of allergic as well as non-allergic asthma.
Airway cells were obtained by sputum induction from 15 healthy and 39 asthmatic individuals and the airway T cell cytokine profiles (interleukin (IL)-4, IL-5, IL-13, IL-10 and interferon (IFN)-gamma) at the mRNA level were studied by real time RT-PCR.
Asthma patients had increased expression of IL-5 (p = 0.001) and IL-13 (p = 0.03) mRNA in sputum compared with non-asthmatic controls. IL-4 mRNA and IFN-gamma mRNA were detectable in the sputum of 44% and 21% of patients, respectively, but not in controls. Sputum IL-10 mRNA levels did not differ significantly between patients and controls. Sputum mRNA expression levels of IL-4, IL-5, and IL-13 were significantly correlated with the percentage of eosinophils and were higher in subjects with allergic asthma than in those with non-allergic asthma (p = 0.03, p = 0.02 and p = 0.0002, respectively); they did not differ between mild asthmatic subjects and those with moderate to severe asthma. In contrast, IFN-gamma mRNA expression was higher in non-allergic than in allergic patients (p = 0.04) and higher in patients with moderate to severe asthma than in those with mild asthma (p<0.01). Sputum IL-5 mRNA levels (but not the other cytokine mRNA levels) were also correlated with exhaled nitric oxide (eNO) and with bronchial hyperreactivity expressed as the histamine concentration resulting in a 20% decrease in forced expiratory volume in 1 second.
Real time RT-PCR analysis of mRNA in induced sputum confirms a predominance of Th2 cytokines in both allergic and non-allergic asthma. IL-5 levels reflect eosinophil infiltration as well as eNO levels and hyperreactivity, and levels of the Th1 cytokine IFN-gamma indicate asthma severity. The technique is a promising tool for use in further studies of asthma severity and disease activity.
It is unknown whether inhaled corticosteroids can modify the subsequent development of asthma in preschool children at high risk for asthma.
We randomly assigned 285 participants two or three years of age with a positive asthma predictive index to treatment with fluticasone propionate (at a dose of 88 mug twice daily) or masked placebo for two years, followed by a one-year period without study medication. The primary outcome was the proportion of episode-free days during the observation year.
During the observation year, no significant differences were seen between the two groups in the proportion of episode-free days, the number of exacerbations, or lung function. During the treatment period, as compared with placebo use, use of the inhaled corticosteroid was associated with a greater proportion of episode-free days (P=0.006) and a lower rate of exacerbations (P<0.001) and of supplementary use of controller medication (P<0.001). In the inhaled-corticosteroid group, as compared with the placebo group, the mean increase in height was 1.1 cm less at 24 months (P<0.001), but by the end of the trial, the height increase was 0.7 cm less (P=0.008). During treatment, the inhaled corticosteroid reduced symptoms and exacerbations but slowed growth, albeit temporarily and not progressively.
In preschool children at high risk for asthma, two years of inhaled-corticosteroid therapy did not change the development of asthma symptoms or lung function during a third, treatment-free year. These findings do not provide support for a subsequent disease-modifying effect of inhaled corticosteroids after the treatment is discontinued. (ClinicalTrials.gov number, NCT00272441.).
Astragaloside IV (AGS-IV), a new glycoside of cycloartane-type triterpene isolated from the root of Astragalus membranaceus (Fisch.) Bunge, has been used experimentally for its potent immune-stimulating, anti-inflammatory, and antioxidative actions. A recent study has shown AGS-IV to be an aldose-reductase inhibitor and a free-radical scavenger. This study examined the effects of AGS-IV on motor nerve conduction velocity (MNCV), tailflick threshold temperature, biochemical indexes, and the histology of the sural nerve after diabetes was induced in rats with 75mg/kg streptozotocin (STZ). AGS-IV (3, 6, 12mg/kg, twice a day) was administered by oral gavage for 12weeks after diabetes was induced. Compared with control (nondiabetic) rats, obvious changes in physiological behaviors and a significant reduction in sciatic MNCV in diabetic rats were observed after 12weeks of STZ administration. Morphological analysis showed that AGS-IV suppressed a decrease in myelinated fiber area, an increase in myelinated fiber density, and an increase in segmental demyelination in diabetic rats. The protective mechanism of AGS-IV involved a decrease in declining blood glucose concentration and HbA1C levels, and an increase in plasma insulin levels. AGS-IV increased the activity of glutathione peroxidase in nerves, depressed the activation of aldose reductase in erythrocytes, and decreased the accumulation of advanced glycation end products in both nerves and erythrocytes. Moreover, AGS-IV elevated Na⁺,K⁺-ATPase activity in both the nerves and erythrocytes of diabetic rats. These results indicate that AGS-IV exerts protective effects against the progression of peripheral neuropathy in STZ-induced diabetes in rats through several interrelated mechanisms.
Few studies have compared treatment strategies in patients with asthma poorly controlled on low dose inhaled corticosteroids, and little is known about the effects of different treatments on airway inflammation. In this double-blind, placebo-controlled, parallel group study, we compared the effects of salmeterol plus fluticasone propionate (FP) (Seretide; SFC) and FP plus montelukast (FP/M) on sputum inflammatory markers, airway responsiveness, lung function, and symptoms in adult asthmatics.
Sixty-six subjects were randomised to SFC or FP/M for 12 weeks. The primary outcome was changes in neutrophil, eosinophil, macrophage, lymphocyte, and epithelial cell levels in induced sputum. Additional outcomes included the change in other sputum markers of airway inflammation, airway responsiveness, symptom control, and lung function.
Both treatments had no significant effect on induced sputum inflammatory cells, although there was a trend for a reduction in sputum eosinophils. Both treatments significantly improved airway responsiveness, whereas SFC generally led to greater improvements in symptom control and lung function than FP/M. FP/M led to significantly greater reductions in sputum cysteinyl leukotrienes than SFC (treatment ratio 1.80; 95% CI 1.09, 2.94).
Both treatments led to similar control of eosinophilic airway inflammation, although PEF and symptom control were better with SFC. STUDY NUMBER: SAM40030 (SOLTA).
Cockroach exposure is a major risk factor for the development of asthma. Inhalation of fecal remnants (frass) is the likely sensitizing agent; however isolated frass has not been tested for its ability to induce experimental asthma in mice.
Mice (Balb/c or C57Bl/6) were sensitized and challenged with GC frass or GC frass devoid of proteases and measurements of airway inflammation and hyperresponsiveness were performed (interleukin (IL)-5, -13, and interferon gamma (IFNgamma) levels in bronchoalveolar lavage fluid, serum IgE levels, airway hyperresponsiveness, cellular infiltration, and mucin production).
Sensitization and challenge of Balb/c mice with GC frass resulted in increased airway inflammation and hyperresponsiveness. C57Bl/6 mice were not susceptible to this model of sensitization; however they were sensitized to GC frass using a more aggressive sensitization and challenge protocol. In mice that were sensitized by inhalation, the active serine proteases in GC frass played a role in airway hyperresponsiveness as these mice had less airway hyperresponsiveness to acetylcholine and less mucin production. Proteases did not play a role in mediating the allergic inflammation in mice sensitized via intraperitoneal injection.
While both strains of mice were able to induce experimental asthma following GC frass sensitization and challenge, the active serine proteases in GC frass only play a role in airway hyperresponsiveness in Balb/c mice that were susceptible to sensitization via inhalation. The differences in the method of sensitization suggest genetic differences between strains of mice.
The regulated expression of adhesion molecules on the surface of endothelial cells is a key process in the pathogenesis of inflammation. The saponin astragaloside IV (AS-IV), a 3-O-beta-D-xylopyranosyl-6-O-beta-D-glucopyranosylcycloastragenol purified from the Chinese medical herb Astragalus membranaceus (Fisch) Bge. has been shown to have anti-inflammatory effects in vivo. In this study we have investigated the effect of AS-IV on cytokine- and LPS-stimulated expression of adhesion molecules in and leukocyte adhesion to endothelial cells. We have demonstrated that AS-IV significantly reduced the adhesion promoting activity of LPS-stimulated HUVECs for polymorph-nuclear leukocytes (PMNs) and the monocytic cell line THP-1. Furthermore, by using specific cell ELISAs we could show that AS-IV decreased the LPS-induced expression of E-selectin and on the surface of HUVECs in a dose and time dependent manner, whereas the expression of ICAM-1 was not affected by AS-IV. AS-IV also inhibits TNFalpha-induced VCAM-1 expression. The saponin octyl-D-glucopyranoside had no effect on the LPS-induced expression of E-selectin and VCAM-1 excluding an unspecific detergent-like effect of AS-IV. Moreover, AS-IV significantly inhibited LPS- and TNFalpha-induced specific mRNA levels for E-selectin and VCAM-1. Finally, we could show that AS-IV completely abolished LPS- and TNFalpha-induced nuclear translocation of NF-kappaB and NF-kappaB DNA binding activity in endothelial cells. We conclude that the ability of AS-IV to inhibit the NF-kappaB pathway might be one underlying mechanism contributing to its anti-inflammatory potential in vivo.
Astragaloside IV, the major active component extracted from Astragalus membranaceus, exerts multipotent activities under pathophysiological conditions. Hyperhomocysteinemia, an independent risk factor for cardiovascular disease, induces oxidative stress leading to endothelial dysfunction. We investigated the effect of astragaloside IV on acute phase endothelial dysfunction induced by homocysteine. In a concentration-dependent manner, endothelial dysfunction was induced by homocysteine. In organ bath experiment using rat aortic rings, treatment with astragaloside IV resulted in an improvement of the impaired endothelium-dependent vasorelaxation by homocysteine as reflected by the higher maximal vasorelaxation to acetylcholine. However, the presence of N(omega)-nitro-L-arginine methyl ester hydrochloride could abolish the protective effect of astragaloside IV on homocysteine-induced vasomotor dysfunction. In human umbilical vein endothelial cells culture experiment, exposure to astragaloside IV significantly ameliorated the homocysteine-induced inactivation of nitric oxide-nitric oxide synthase signal pathway via reducing oxygen species and increasing the activity of superoxide dismutase. Additionally, pretreatment with superoxide dismutase showed a similar effect to astragaloside IV on attenuation of the homocysteine-induced endothelial dysfunction. These data support the view that astragaloside IV might be advantageous in the treatment of endothelial dysfunction induced by disturbed nitric oxide-nitric oxide synthase pathway due to oxidative stress in hyperhomocysteinemia.
Airway hyperresponsiveness (AHR) in asthmatics includes a variable component that persists following an allergen challenge. This may be dissociated from inflammatory cell recruitment, implying a role for resident pulmonary cells in regulating the response.
Using improved methods of assessing AHR in a mouse model of allergic airway disease, to investigate the basis of the development of prolonged AHR.
BALB/c mice were systemically sensitized and then challenged with aerosolized ovalbumin (OVA). Airway and tissue responsiveness were measured at baseline and at 1 day, and 1, 2 and 3 weeks after the last OVA challenge. Inflammatory cell numbers in BALF and levels of mRNA for eotaxin-1 and -2, IFN-gamma, IL-5 and -13 in the lung were measured at each time-point. In further experiments, the roles of IFN-gamma and of CCR3(+) and CD4(+) cells in the development of prolonged AHR were assessed by blockade or depletion with monoclonal antibodies. The role of pulmonary macrophages was assessed by selective chemical depletion of these cells.
Airway responsiveness was increased above baseline at 1 day after the last OVA challenge, and this was sustained for 1 week. In contrast, tissue-specific responsiveness was only significantly increased above baseline at 1 day. Development of prolonged AHR was inhibited by neutralization of IFN-gamma or by depletion of pulmonary macrophages, but not by depletion of either CD4(+) T cells or CCR3(+) eosinophils.
An interaction between IFN-gamma and pulmonary macrophages contributed to the prolongation of airway hyperresponsiveness. In contrast, T cells and eosinophils did not contribute to prolongation of AHR. These findings emphasize the importance of the innate host response in the development of manifestations of asthma, as well as its potential relevance as a target for therapeutic intervention.
Vitamin C is traditionally regarded to be beneficial for asthma, however the benefit is still controversial. In the present study, high dose vitamin C was supplemented to ovalbumin (OVA)-sensitized and challenged mice to evaluate the effects of dietary vitamin C on allergic asthma. In this study, the experimental mice were divided into four groups, including nonsensitized control, dietary control, positive control (cured ip with dexamethasone), and high dose vitamin C supplementation (130 mg of vitamin C/kg bw/day by gavage for 5 weeks). Differential leukocyte counts, levels of inflammatory mediators, as well as type 1 T-helper lymphocytes (Th1)-type and type 2 T-helper lymphocytes (Th2)-type cytokines in the bronchoalveolar lavage fluid (BALF) were determined. The results showed that both high dose vitamin C supplementation and dexamethasone treatments significantly (P < 0.05) decreased eosinophilic infiltration into BALF. High dose vitamin C supplementation significantly increased the secretion ratio of interferon (IFN)-gamma/interleukin (IL)-5 cytokines. This study suggests that high dose vitamin C supplementation might attenuate allergic inflammation in vivo via modulating the Th1/Th2 balance toward the Th1 pole during the Th2-skewed allergic airway inflammation and decreasing eosinophilic infiltration into BALF.
Hepatic glycogen phosphorylase (GP) and glucose-6-phosphatase (G6Pase) are important in control of blood glucose homeostasis, and are considered to be potential targets for antidiabetic drugs. Astragaloside IV has been reported to have a hypoglycemic effect. However, the biochemical mechanisms by which astragaloside IV regulates hepatic glucose-metabolizing enzymes remain unknown. The present study examines whether GP and G6Pase mediate the hypoglycemic effect of astragaloside IV.
Type 2 diabetic mice were treated with astragaloside IV for 2 weeks. Blood glucose and insulin levels were measured by a glucometer and the ELISA method, respectively. Total cholesterol (TC) and triglyceride (TG) levels were determined using Labassay kits. Activities of hepatic GP and G6Pase were measured by the glucose-6-phosphate dehydrogenase-coupled reaction. The mRNA and protein levels of both enzymes were determined by real-time RT-PCR and Western blotting.
Astragaloside IV at 25 and 50 mg/kg significally decreased the blood glucose, TG and insulin levels, and inhibited the mRNA and protein expression as well as enzyme activity of GP and G6Pase in diabetic mice.
Astragaloside IV exhibited a hypoglycemic effect in diabetic mice. The hypoglycemic effect of this compound may be explained, in part, by its inhibition of hepatic GP and G6Pase activities.
Astragaloside IV is the primary pure saponin isolated from Astragalus membranaceus, one of the valuable traditional medical herbs. Antifibrotic activities of Astragalus membranaceus have been extensively proved.
To investigate the effects of astragaloside IV on hepatic stellate cells (HSCs) and hepatic fibrosis in rats induced by porcine-serum (PS).
Liver fibrosis was induced by PS injection (0.5 ml, twice a week) for 12 weeks. Astragaloside IV (2.0, 4.0 mg kg(-1)) was administered intragastrically. Liver samples were subjected to histological and immunohistochemical studies. In vitro effects of astragaloside IV on primary cultured HSCs were detected by incorporation assays.
Astragaloside IV delayed the formation of liver fibrosis and decrease the serum levels of hyaluronic acid (HA), procollagen type III (PCIII) and hydroxyproline (Hyp) content in liver. The levels of transforming growth factor-beta(1) (TGF-beta(1)) in serum and expression in liver were significantly decreased by astragaloside IV. Collagen synthesis and proliferation were significantly inhibited by astragaloside IV (1.5, 3.0, 6.0, 12.0 and 24.0 mg L(-1)) in HSCs.
The results showed that astragaloside IV displays antifibrotic effects in rats induced by PS, the mechanism by which might be associated with its inhibitory effects on collagen synthesis and proliferation in HSCs.
Astragalus membranaceus is widely used to treat stroke and chronic debilitating diseases in China, but the mechanism has not been fully demonstrated to data. In the present study, we, using astragaloside IV, a purified extract from astragalus membranaceus, to a focal cerebral ischemia/reperfusion rat model, aimed to investigate the effect of astragaloside IV on the permeability of the blood-brain barrier since disruption of blood-brain barrier induced by ischemia/reperfusion leads to serious brain injuries. We found that astragaloside IV (10, 20 mg/kg) significantly attenuated the permeability of blood-brain barrier in comparison with vehicle group after ischemia/reperfusion assessed via Evans blue leakage (P<0.05). This was further confirmed by examination of blood-brain barrier permeability under the electron microscope, using lanthanum as a tracer of blood vessel permeability. Lanthanum was usually found within the blood vessel in sham group, rather than in perivascular tissues as shown in vehicle group. In drug groups, lanthanum stain was mainly restricted within the cerebral capillary, indicating the potential protective effect of astragaloside IV on the integrity of blood-brain barrier in ischemia/reperfusion rats. Furthermore, we found that expression of occludin and zonae occludens-1 (ZO-1), the tight junction proteins, was decreased in endothelial cells in vehicle group, which, however, could be reversed by astragaloside IV administration. We propose that regulation of tight junctional proteins in the endothelial cells may be one mechanism astragaloside IV-mediated in attribution to blood-brain barrier protection in the ischemia/reperfusion rats.
A thickened bronchial epithelial basement membrane has long been regarded as a histopathologic characteristic of bronchial asthma. As we had previously demonstrated that this phenomenon is due to the deposition of interstitial collagens and fibronectin, we have now sought to determine the nature of the cell responsible for this process by studying endobronchial biopsies from eight normal and seven asthmatic volunteers by immunohistochemistry and electron microscopy. Biopsies were stained with PR 2D3, a monoclonal antibody to myofibroblasts of the pericrypt sheath of the colon and a monoclonal antibody to alpha-smooth muscle actin. The thickness of the subepithelial collagen and the organelle content of the cells therein were determined by electron microscopy. The subepithelial collagen thickness in the normal subjects ranged from 2.16 to 6.26 microns, while that in the asthmatic subjects ranged from 3.75 to 11.1 microns (Mann-Whitney test; P = 0.05). Elongated cells in the collagen layer were identified by staining with PR 2D3. As this antibody also stains smooth muscle, consecutive frozen sections were stained for alpha-smooth muscle actin and the number of positive cells per millimeter of basement membrane was subtracted from the count for PR 2D3. This yielded a count of 4.9 to 9.4 cells/mm in the normal subjects and 11.9 to 20.6 cells/mm in the asthmatics (P = 0.001). There was a highly significant correlation between the depth of subepithelial collagen and the number of PR 2D3-positive, alpha-smooth muscle actin-positive cells (Spearman rank correlation; r = 0.764 and P = 0.006). Electron microscopy confirmed the myofibroblastic nature of these cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Asthma is characterized by inflammation, reversible airway obstruction, and increased airway responsiveness to various stimuli. It has received wide public attention in recent years because of increasing morbidity and deaths, particularly among black persons. The important role of inflammation in the immunopathogenesis of asthma has led to a newer therapeutic approach directed at interrupting this inflammatory process. Among immune regulatory pathways involved in asthma pathogenesis, two lymphokines appear to be particularly important in controlling IgE production. Interleukin-4 is required for IgE production; without it, IgE production is inhibited. Interferon-gamma can diminish cell priming for interleukin-4 production. Thus, the interplay of these two cytokines will determine whether cells that can make interleukin-4 will be produced and, therefore, whether IgE will be produced in response to allergic stimuli. Further, in response to appropriate stimuli, mast cells and eosinophils are attracted to airways and release cytokines, lipid mediators, and preformed substances that cause inflammation. Modern asthma treatment is directed at interrupting this inflammatory process and places a much greater emphasis on use of anti-inflammatory agents, such as aerosolized or parenteral corticosteroids, and on non-steroidal anti-inflammatory agents, such as cromolyn sodium and nedocromil sodium. Research advances without therapeutic application, however, limit success. Projects such as the National Institute of Allergy and Infectious Diseases' National Cooperative Inner-City Asthma Study, which is directed toward underserved populations, are intended to identify more clearly the factors responsible for increasing morbidity and to develop appropriate therapeutic interventions.
To investigate the effect of astragaloside IV (ASI) on T, B lymphocyte proliferation, antibody production, and cytokines produced by murine peritoneal macrophages.
MTT assay was used to determine T, B lymphocyte proliferation and quantitative hemolysin spectrophotometry (QHS) assay was applied to test antibody production; IL-1 production was measured by thymocyte proliferation assay; TNF-alpha production was determined by the cytotoxicity assay against L929 cells.
1) In vivo, ASI 50-200 mg/kg ig for 7 d increased T lymphocyte proliferation and antibody production, and ASI 50-100 mg/kg ig for 7 d increased B lymphocyte proliferation but ASI 200 mg/kg had no effect on B lymphocyte proliferation; 2) In vitro, ASI increased T, B lymphocyte proliferation only at 100 nmol/L; 3) ASI increased IL-1 activity at 1 nmol/L in vitro, but decreased it at 100 and 1000 nmol/L; 4) ASI inhibited TNF-alpha activity with or without LPS-stimulation in vitro.
ASI increased T, B lymphocyte proliferation and antibody production in vivo and in vitro; but inhibited productions of IL-1 and TNF-alpha from peritoneal macrophages in vitro.
To explore the effects of astragaloside IV (XGA) on myocardial calcium transport and cardiac function in ischemic rats.
Eighty-four Wistar rats were divided into three groups: control group (n=12); ischemic group (n=12) was given isoprenaline injection sc at a dose of 30 mg/kg; and XGA group (n=60) was given XGA after isoprenaline administration. The changes of the parameters of hemodynamics, cardiac function, and intra- and extracellular calcium concentration of the myocardial cells were determined. The dose- and time-effect relationship of XGA on myocardial calcium transport and cardiac function were observed.
After XGA administration, there was significant improvement in cardiac function and hemodynamics in ischemic rats. The cardiac output, heart rate, stroke volume, mean aortic pressure, systolic aortic pressure, the stroke work of left ventricule, the right and left ventricle systolic pressure, and +dp/dt of the right ventricle of ischemic rats gradually recovered to the level of the control group with increasing the dose of XGA and prolongation of the action of XGA. The ionized calcium of the myocardium and the total amount of calcium of the myocardial tissue decreased markedly compared to those in ischemic group, and the activity of calcium pump of erythrocyte membrane increased significantly in comparison to that of ischemic group, but their changes had no trend of increase with increasing dose of the XGA. However, there was a gradual decrease of the ionized calcium of the myocardium with the prolongation of acting time of XGA.
XGA improves the cardiac function in ischemic rats, and the reduction of excessive accumulation of intracellular calcium within myocardial cells plays an important role.
Although inhaled glucocorticosteroids are recommended for persistent asthma, their long-term effect on recent onset, mild, persistent asthma has yet to be established.
We did a randomised, double-blind clinical trial in 7241 patients in 32 countries to assess the effects of budesonide in patients who had had mild persistent asthma for less than 2 years and who had not had previous regular treatment with glucocorticosteroids. Patients aged 5-66 years received either budesonide or placebo once daily for 3 years in addition to their usual asthma medications. The daily budesonide dose was 400 microg, or 200 microg for children younger than 11 years. The primary outcome was time to first severe asthma-related event, and analysis was by intention to treat.
198 of 3568 patients on placebo and 117 of 3597 on budesonide had at least one severe asthma exacerbation; hazard ratio 0.56 (95% CI 0.45-0.71, p<0.0001). Patients on budesonide had fewer courses of systemic corticosteroids and more symptom-free days than did those on placebo. Compared with placebo, budesonide increased postbronchodilator forced expiratory volume in 1 s (FEV1) from baseline by 1.48% (p<0.0001) after 1 year and by 0.88% (p=0.0005) after 3 years (expressed as percent of the predicted value). The corresponding increase in prebronchodilator FEV1 was 2.24% after 1 year and 1.71% after 3 years (p<0.0001 at both timepoints). The effect of treatment on all outcome variables was independent of the baseline lung function (prebronchodilator or postbronchodilator) or baseline medication. In children younger than 11 years, 3-year growth was reduced in the budesonide group by 1.34 cm. The reduction was greatest in the first year of treatment (0.58 cm) than years 2 and 3 (0.43 cm and 0.33 cm, respectively).
Long-term, once-daily treatment with low-dose budesonide decreases the risk of severe exacerbations and improves asthma control in patients with mild persistent asthma of recent onset.
Astragalus membranaceus is a herbal medicine that has been used clinically in stroke patients in China for decades, but its potential neuroprotective effect against ischemic brain injury has not been experimentally tested. In this study, we investigated the effect of Astragaloside IV, a purified extract from Astragalus membranaceus, in a murine model of focal cerebral ischemia/reperfusion produced by transient (1.5 h) middle cerebral artery occlusion. As determined at 72 h after ischemia, post-ischemic treatment of Astragaloside IV (20 or 40 mg/kg) markedly and significantly (P < 0.03 vs. vehicle-treated animals) reduced infarct volume. Astragaloside IV treatment also decreased the levels of malondialdehyde, an indicator of lipid peroxidation, and increased the levels of the antioxidant enzymes glutathione peroxidase and superoxide dismutase in ischemic tissues. The results presented here provide the first evidence of a neuroprotective effect of Astragaloside IV in the model of ischemic brain injury. We suggest that the anti-infarction effect by Astragaloside IV may be derived at least in part from its antioxidant properties.
This review examines recent articles on the relationship of cytokines to allergy and asthma with particular emphasis on immune mechanisms involved in disease development in early life.
It was previously proposed that reduced microbial exposure in early life is responsible for a shift of the Th1/Th2 balance in the immune system towards the proallergenic Th2 response. This Th1/Th2 imbalance results in the clinical expression of allergy and/or asthma. In recent years, accumulating data from mice and humans have identified Th2 cytokines [interleukin (IL)-4, IL-13, and IL-5] as major contributors to allergy and asthma. Interestingly, the Th1 cytokine interferon-gamma has recently been shown to act concurrently with Th2 cytokines in maintaining the chronic inflammatory response in allergic diseases, particularly in asthmatic airways. Most recently, evidence suggests that suppression of T-regulatory cells may contribute to the underlying immune mechanisms involved in allergy and asthma.
An enhanced Th2 immune response and the elaboration of cytokines such as IL-4, IL-13, and IL-5 contribute to the induction of allergy and asthma. Interferon-gamma, a Th1 cytokine, acts in conjunction with Th2 (IL-4, IL-13, and IL-5) in maintaining chronic allergic inflammation. The mechanisms leading to an enhanced Th2 response are still controversial. Th2-dominated immune responses may result from immune suppression of T-regulatory cells as well as Th1 cells. Understanding early-life immune mechanisms responsible for atopic diseases, specifically how cytokines of T-regulatory cells act to balance the Th1 and Th2 immune response, continues to be a fruitful area of research.
Astragaloside IV is the major active constituent of Astragalus membranaceus, which has been widely used for the treatment of cardiovascular diseases in China. However, the effects of astragaloside IV on myocardial ischemia and its mechanisms of action remain largely unknown. In this study, we have examined the effects of astragaloside IV on myocardial infarction and coronary flow in vivo and in vitro. The possible roles of its antioxidative and nitric oxide-inducing properties were also explored. Astragaloside IV significantly reduced infarct size in dogs subjected to coronary ligation in vivo. Astragaloside IV also improved post-ischemic heart function and ameliorated reperfusion arrhythmias in rat hearts in vitro. The cardioprotection of astragaloside IV was accompanied by a significant increase in coronary flow both in vivo and in vitro. The nitric oxide synthase inhibitor, Nomega-nitro- L-arginine methyl ester partially abrogated astragaloside IV's protective effect on heart function. Myocardial antioxidative enzyme superoxide dismutase activity increased with astragaloside IV administration. These data suggest the potential roles of antioxidative and nitric oxide-inducing properties of astragaloside IV in its protection from myocardial ischemia.
Coxsackievirus B3 (CVB3) is a major pathogen for viral myocarditis and dilated cardiomyopathy in children and young adults. The aim of this study was to determine the antiviral effects of astragaloside IV against CVB3, and the underlying mechanism. First, we evaluated antiviral effects of astragaloside IV in vitro by measuring the virus titers of CVB3 in primarily cultured myocardial cells infected with CVB3, and in vivo by assessing the morbidity, mortality, heart-to-body weight ratio (HW/BW), and virus titers in BALB/c mice infected with CVB3. Then, we performed serum pharmacological experiments by testing the effect of sera from SD rats treated with astragaloside IV on proliferation of CVB3 in primarily cultured myocardial cells. Finally, we determined the effect of astragaloside IV on IFN-gamma mRNA expression in the hearts of infected BALB/c mice. We observed that astragaloside IV decreased virus titers of CVB3 in primarily cultured myocardial cells. Morbidity, mortality, HW/BW, and virus titers all decreased, and necrosis and mononuclear cell infiltration were alleviated in CVB3-infected mice treated with astragaloside IV, compared with those infected mice without the treatment. In addition, proliferation of CVB3 was inhibited by the sera of rats treated with astragaloside IV. Moreover, we observed that IFN-gamma mRNA expression was increased in mice treated with astragaloside IV. Therefore, we conclude that astragaloside IV exerts antiviral effects against CVB3 by upregulating expression of IFN-gamma mRNA.
The purpose of the present study was to examine the effects of astragaloside IV, a saponin isolated from Astragalus membranaceus (Fisch) Bge, on the impairment of barrier function induced by acute high glucose in cultured human vein endothelial cells. High glucose (27.8 mM) induced a decrease in transendothelial electrical impedance and an increase in cell monolayer permeability in human umbilical vein endothelial cells. Endothelial barrier dysfunction stimulated by high glucose was accompanied by translocation and activation of protein kinase C (PKC), the redistribution of F-actin and formation of intercellular gaps, suggesting that increases in PKC activity and rearrangement of F-actin could be associated with endothelial barrier dysfunction induced by acute high glucose. Application of astragaloside IV inhibited high glucose-induced endothelial barrier dysfunction in a dose-dependent manner, which is compatible with inhibition of PKC translocation and improvement of F-actin rearrangements. Western blot analysis revealed that high glucose-induced PKC alpha and beta2 overexpression in the membrane fraction were significantly reduced by astragaloside IV. These findings indicate that astragaloside IV protected endothelial cells from high glucose-induced barrier impairment by inhibiting PKC activation, as well as improving cytoskeleton remodeling.
The major active constituent of Astragalus membranaceus, astragaloside IV, has been found to have properties of increasing coronary flow and cardioprotection. In this study, we examined the direct effects of astragaloside IV on vessel dilatation and contraction in isolated aortic rings from both normal and stroke-prone spontaneously hypertensive rats (SHR-SP) in vitro. The results demonstrated that astragaloside IV could antagonize vessel contractions induced by phenylephrine and potassium chloride in a concentration-dependent way. Astragaloside IV reduced CaCl2-induced contractions in Ca2+-free solution. Astragaloside IV also dilated aortic vessels in a dose-dependent manner, which was partially endothelium-dependent through the nitric oxide (NO) and cGMP pathways. The aorta from 6-month-old SHR-SP rats showed impaired endothelium function, and astragaloside IV dilated the vessels from the hypertensive rats to a lesser extent as compared with normal control rats. In the presence of perivascular fat tissue, the contractile responses induced by angiotensin II and phenylephrine were also attenuated by astragaloside IV. Collectively, this study provides functional evidence that astragaloside IV exerts vessel dilatation properties through the endothelium-dependent NO-cGMP pathway in normal and hypertensive rats. It blocks extracellular calcium influx and participates in vessel relaxation partly through phenylephrine and angiotensin II inhibition when perivascular fat is present.
1. Astragaloside IV is a component from the widely used traditional Chinese herb Astragalus membranaceus and its effect on rat aortic ring contraction and relaxation were investigated. 2. The aorta from male Sprague-Dawley rats was isolated in an organ bath and ring tension was recorded with or without endothelium. Cumulative effects of astragaloside IV on vessel contraction and relaxation were observed in the presence of various antagonists related to vessel activity. 3. Astragaloside IV showed concentration-dependent inhibition of vessel contraction induced by phenylephrine and potassium chloride. The amount of calcium released from intracellular stores sensitive to phenylephrine was also markedly reduced by astragaloside IV. There was dose-dependent vasorelaxation in endothelium-intact rings, which was partly inhibited by pre-incubation with nitric oxide (NO) synthase (NOS) Nomega-nitro-L-arginine methyl ester and guanylate cyclase inhibitor, 1H-[1,2,4] oxadiazolo [4,3-alpha] quinoxalin-1-one. Astragaloside IV also induced a significant increase in aortic tissue content of guanosine 3",5"-cyclic monophosphate (cGMP) both in vivo and in vitro. Endothelial NOS inhibitor Nomega-nitro-L-arginine prevented vasodilatation, whereas neuronal NOS inhibitor 7-nitroindazole did not show significant influence on the vessel relaxation of astragaloside IV. 4. In conclusion, astragaloside IV inhibited vessel contraction through blocking calcium influx and intracellular calcium release. The endothelium-dependent vessel dilation of astragaloside IV was attributed mainly to the endothelium-dependent NO-cGMP pathway.
Astragaloside IV, the primary pure saponin isolated from Astragalus membranaceus has been found to have potent cardioprotective effects. In this study, we aim to investigate if the beneficial effects of astragaloside IV on cardiac function are associated with improvement in sarcoplasmic reticulum Ca(2+)-pump function in myocardial injury in vivo. Myocardial injury in rats was induced by subcutaneous injection of a high dose of isoproterenol, and the therapeutic effect of astragaloside IV was observed. Isoproterenol-treated rats showed widespread subendocardial necrosis, a rise in serum lactate dehydrogenase and creatine kinase, formation of lipid oxide product malondialdehyde and inhibition of left ventricular diastolic and systolic function, which suggested severe myocardial injury and acute heart failure. Moreover, sarcoplasmic reticulum Ca(2+)-uptake ability and Ca(2+)-ATPase (SERCA2a) activity were significantly reduced. And the level of SERCA2a mRNA and protein expression was also markedly decreased, associated with a decrease in Ser(16)-phosphorylated phospholamban protein expression, while total phospholamban level was unchanged in the isoproterenol-treated group compared with controls. However, these biochemical and hemodynamic changes in the acute failing hearts were prevented by treatment of isoproterenol-induced rats with astragaloside IV. Likewise, the observed reductions in sarcoplasmic reticulum Ca(2+)-pump function as well as in SERCA2a mRNA and protein levels and the phosphorylation level of phospholamban in the injured hearts were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV on isoproterenol-induced myocardial injury may be due to its ability to prevent changes of SERCA2a and Ser(16)-phosphorylated phospholamban protein expression and, thus, may prevent the depression in sarcoplasmic reticulum Ca(2+) transport and improve cardiac function.
In a mouse model of mild chronic asthma, both inflammation and remodelling can be suppressed by dexamethasone (a glucocorticoid) and roflumilast (a selective phosphodiesterase-4 inhibitor).
To better understand the underlying molecular mechanisms, we investigated the effects of treatment on airway expression of inflammation-related cytokines, as well as on epithelial expression of growth factors.
BALB/c mice systemically sensitized to ovalbumin were challenged with aerosolized antigen for 6 weeks and treated with roflumilast or dexamethasone during the final 2 weeks. Expression of mRNA, for a variety of cytokines and growth factors, was assessed in selectively dissected proximal airways or in airway epithelium obtained by laser capture microdissection.
In the airway wall of vehicle-treated challenged animals, there was significantly elevated expression of mRNA for a variety of pro-inflammatory and T helper type 2 cytokines, as well as for IFN-gamma. All these cytokines were suppressed by dexamethasone. Treatment with roflumilast reduced expression of IL-17A, TNF-alpha, granulocyte-macrophage colony-stimulating factor and IL-6, but did not inhibit other cytokines. Both drugs suppressed the enhanced expression of mRNA for growth factors such as TGF-beta1 and FGF-2 in airway epithelium.
Whereas dexamethasone non-specifically inhibits numerous mediators involved in inflammation and the immune response, roflumilast selectively inhibits a subset of pro-inflammatory cytokines and growth factors. These mediators and/or the cells that produce them may have critical roles in the pathogenesis of the lesions of chronic asthma.
It has been suggested that exposure to certain microbes and their products, particularly during neonatal and early childhood periods, may shift the immune response towards a T-helper cell (Th) 1 phenotype and thereby prevent the development of and/or alleviate the clinical symptoms of allergic airway diseases.
We evaluated the ability of the live vaccine strain (LVS) of Francisella tularensis to suppress airway eosinophilia and pulmonary pathology in a murine model of allergic airway disease.
C57BL/6 mice were sensitized by intraperitoneal injection of ovalbumin (OVA) on days 1 and 14, and challenged intranasally (i.n.) with OVA on day 21 or thereafter. Some sensitized mice were i.n. treated with live LVS or its cell-free sonicate extract (CFSE) before i.n. OVA challenge. Bronchoalveolar lavage fluid, regional lymph node cells, lung tissues and serum samples were collected 3-7 days after the i.n. challenge.
Intranasal and, to a lesser degree, intradermal immunization of OVA-sensitized mice with LVS suppressed the development of airway eosinophilia and associated pulmonary pathology induced by i.n. OVA challenge. Moreover, CFSE prepared from LVS showed a similar inhibitory effect whereas neither LPS nor DNA purified from F. tularensis LVS had such an effect. The inhibition was associated with the reduction in mRNA expression and protein levels of Th2 cytokines IL-5 and IL-13 in the lungs and the enhanced production of OVA-induced IFN-gamma by local draining lymph node cells, but not with the serum levels of OVA-specific IgG1 or IgE.
F. tularensis LVS is capable of suppressing allergic airway inflammation probably through a Th1-mediated suppression of an ongoing Th2 response mechanism, and raises the possibility of exploring LVS and its components as potential therapeutic modalities for human allergic asthma.
The mechanisms underlying airway hyperresponsiveness remain unclear, although airway inflammation and remodeling likely play important roles. We have observed sustained airway hyperreactivity and airway remodeling occurring in mice after chronic allergen exposure and persisting beyond resolution of allergen-induced inflammation. The aim of this study was to delineate mechanisms involved in allergen-induced airway hyperreactivity and airway remodeling and to examine evidence for a causal association between airway remodeling and sustained airway hyperreactivity. Wild-type (WT) and interleukin (IL)-4-, IL-5-, and IL-13-deficient (-/-) mice were sensitized and studied 4 weeks after chronic allergen exposure. By measuring airway responsiveness and airway morphometry, we demonstrated that WT mice developed sustained airway hyperreactivity and aspects of airway remodeling after chronic allergen exposure. Both IL-4(-/-) and IL-13(-/-) mice were protected from developing sustained airway hyperreactivity and aspects of airway remodeling. In contrast, IL-5(-/-) mice developed sustained airway hyperreactivity and aspects of airway remodeling similar to that seen in WT mice. Our results confirm that IL-4 and IL-13, but not IL-5, are critical for the development of sustained airway hyperreactivity and airway remodeling after allergen exposure.
Although astragaloside IV, a saponin isolated from Astragalus membranaceus, has been shown to protect the myocardium against ischemia/reperfusion injury, its effect on the status of sarcoplasmic reticulum (SR) Ca2+ transport in the injured myocardium remains largely unknown. In this study, we investigated whether in cultured cardiomyocytes subjected to hypoxia and reoxygenation (H/R) administration of astragaloside IV during H/R attenuates the myocardial cell injury and prevents changes in Ca2+ handling activities and gene expression of SR Ca2+ pump. Cultured cardiomyocytes from neonatal rats were exposed to 6 h of hypoxia followed by 3 h of reoxygenation. Myocyte injury was determined by the release of cardiac troponin I in supernatant. Astragaloside IV significantly inhibited cardiac troponin I release after H/R in a dose-dependent manner. The diastolic [Ca2+]i measured with Fura-2/AM was significantly increased after reoxygenation. Astragaloside IV prevented the rise of diastolic [Ca2+]i and the depression of caffeine-induced Ca2+ transients caused by H/R. Furthermore, the observed depressions in SR Ca2+-ATPase activity as well as the mRNA and protein expression of SR Ca2+-ATPase in hypoxic-reoxygenated cardiomyocytes were attenuated by astragaloside IV treatment. These results suggest that the beneficial effect of astragaloside IV in H/R-induced injury may be related to normalization of SR Ca2+ pump expression and, thus, may prevent the depression in SR Ca2+ handling.
Understanding the mechanisms of airway remodeling in chronic allergic conditions such as asthma is increasingly dependent on the use of animal models. Techniques for quantifying structural changes are required that are reproducible and responsive and that can be applied to different staining techniques in both human and animal airway tissues. Here, we characterize a morphometric technique to quantify changes in extracellular matrix and contractile tissue as two indices of airway remodeling in mice. Specific aims were to establish the optimum projection beneath the epithelium to assess remodeling changes and to determine whether such changes are reproducible within different areas of the lung. Finally, based on the variance within measurements, we calculated sample size requirements for research applications of this technique. BALB/c mice were sensitized to ovalbumin and studied after chronic allergen challenge. Lungs were formalin fixed and sectioned were then assayed for extracellular matrix or contractile tissue using morphometric/colorimetric techniques. In this model, the optimum projected distance to measure changes in extracellular matrix or contractile tissue was 20 micro m beneath the epithelium; projecting beyond this depth resulted in decreased ability to detect allergen-induced changes (signal) because of increased irrelevant staining of surrounding parenchymal tissue (noise). The technique was responsive, because an allergen-induced signal was detected in all airway sections and all lung regions studied (p < 0.05). The power of this analysis was such that allergen-induced changes can be reliably (>80% power) detected using 8 to 10 mice. This morphometric technique provides a valid and objective method to assess structural changes in the airways of mice after chronic allergen exposure.
Astragaloside IV is one of the main active ingredients of Radix astragali, which is a herbal remedy widely used in traditional Chinese medicine for the treatment of diabetes and cardiovascular diseases. However, its effects on vascular smooth muscle cell (VSMC), which plays a key role in the development of diabetic vascular complications, were not well studied. The present study was performed to examine the effects of astragaloside IV on proliferation, apoptosis and phenotypic modulation of VSMC under high D-glucose (25 mM). Application of astragaloside IV inhibited the proliferation and the rise of the proliferation index (PI) of VSMC induced by high glucose in a dose-dependent manner. Astragaloside IV induced apoptosis in VSMC under high glucose conditions, accompanied with typical morphological alterations and loss of mitochondrial membrane potential (ΔΨ m). In addition, Western blot analysis revealed that astragaloside IV increased the expression of α-smooth muscle actin, an important phenotypic modulation marker. In conclusion, astragaloside IV could inhibit high glucose-induced VSMC proliferation through intervention with the cell cycle, promoting apoptosis and regulating phenotypic modulation of VSMC, which strongly suggest that astragaloside IV could hinder the process of pathological vascular remodeling in diabetic patients.
Abbreviations
α-SMA:alpha-smooth muscle actin
AS-IV:astragaloside IV
DMEM:Dulbecco's modified Eagle's medium
EDTA:ethylenediaminetetraacetic acid
FCS:fetal calf serum
FITC:fluorescein isothiocyanate
HG:high glucose
NG:normal glucose
PBS:phosphate-buffered saline
PI:proliferative index
RSG:rosiglitazone
SDS:sodium dodecyl sulfate
SDS-PAGE:sodium dodecylsulfate polyacrylamide gel electrophoresis
VSMC:vascular smooth muscle cells