[Show abstract][Hide abstract] ABSTRACT: Background/purpose
Chlorhexidine (CHX), a chlorophenyl biguanide with broad antibacterial action, has been widely used in dentistry. The initial uses of CHX in dentistry were to wash operation site and to disinfect root canals. Recently, the addition of CHX into many dental materials has improved the overall therapeutic efficacy. The aim of this study was to evaluate the potential toxicological implications of CHX employing an in vitro mammalian test system.
Materials and methods
Cytotoxicity, mode of cell death, and generation of superoxide anion were performed to elucidate the toxic effects of CHX on Chinese hamster ovary cells. Cytotoxicity was judged using tetrazolium bromide reduction assay. The mode of cell death was determined by flow cytometry. Superoxide anion generation was determined by the superoxide dismutase-inhibitable reduction of ferricytochrome c.
CHX demonstrated a cytotoxic effect on Chinese hamster ovary cells in a dose-dependent and time-dependent manner (P < 0.05). The mode of cell death changed from apoptosis to necrosis as the concentrations of CHX elevated. CHX demonstrated a significant superoxide anion generation in a dose-dependent manner (P < 0.05). The addition of superoxide dismutase decreased the cytotoxicity induced by CHX (P < 0.05).
CHX was demonstrated to exhibit cytotoxicity that could disrupt the stable cellular redox balance, resulting in increasing levels of free radical generation and subsequent cell death. CHX has significant potential for cytotoxicity.
Full-text · Article · Jun 2014 · Journal of dental sciences
[Show abstract][Hide abstract] ABSTRACT: Acute lung injury (ALI) is a serious disease with unacceptably high mortality and morbidity rates. Up to now, no effective therapeutic strategy for ALI has been established. Rutin, quercetin-3-rhamnosyl glucoside, expresses a wide range of biological activities and pharmacological effects, such as anti-inflammatory, anti-hypertensive, anti-carcinogenic, vasoprotective, and cardioprotective activities. Pretreatment with rutin not only inhibited histolopatholgical changes in lung tissues but also infiltration of polymorphonuclear granulocytes (PMNs) into bronchoalveolar lavage fuild (BALF) in LPS-induced ALI. In addition, LPS-induced inflammatory responses, including increased secretion of proinflammatory cytokines and lipid peroxidation, were inhibited by rutin in a concentration-dependent manner. Furthermore, rutin suppressed phosphorylation of NF-κB and MAPK, and degradation of IκB, a NF-κB inhibitor. Decreased activities of antioxidative enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and hemeoxygenase (HO)-1 caused by LPS were reversed by rutin. At the same time, we found that ALI amelioration by chelation of extracellular metal ions with rutin is more efficacious than with deferoxamine. These results indicated that the protective mechanism of rutin is by inhibition of MAPK-NFκB activation and up-regulation of antioxidative enzymes.
Full-text · Article · Jan 2014 · Free Radical Biology and Medicine
[Show abstract][Hide abstract] ABSTRACT: Bisphenol A-glycidyl-methacrylate (BisGMA) employs as a monomer in dental resins. The leakage of BisGMA from composite resins into the peripheral environment can result in inflammation via macrophage activation. Prostaglandin E2 (PGE2) is a key regulator of immunopathology in inflammatory reactions. Little is known about the mechanisms of BisGMA-induced PGE2 expression in macrophage. The aim of this study was to evaluate the signal transduction pathways of BisGMA-induced PGE2 production in murine RAW264.7 macrophages.
Herein, we demonstrate that BisGMA can exhibit cytotoxicity to RAW264.7 macrophages in a dose- and time-dependent manner (p<0.05). In addition, PGE2 production, COX-2 expression, and cPLA2 phosphorylation were induced by BisGMA on RAW264.7 macrophages in a dose- and time-dependent manner (p<0.05). Moreover, BisGMA could induce the phosphorylation of ERK1/2 pathway (MEK1/2, ERK1/2, and Elk), p38 pathway (MEK3/6, p38, and MAPKAPK2), and JNK pathway (MEK4, JNK, and c-Jun) in a dose- and time-dependent manner (p<0.05). Pretreatment with AACOCF3, U0126, SB203580, and SP600125 significantly diminished the phosphorylation of cPLA2, ERK1/2, p38, and JNK stimulated by BisGMA, respectively (p<0.05). BisGMA-induced cytotoxicity, cPLA2 phosphorylation, PGE2 generation, and caspases activation were reduced by AACOCF3, U0126, SB203580, and SP600125, respectively (p<0.05).
These results suggest that BisGMA induced-PGE2 production may be via COX-2 expression, cPLA2 phosphorylation, and the phosphorylation of MAPK family. Cytotoxicity mediated by BisGMA may be due to caspases activation through the phosphorylation of cPLA2 and MAPKs family.
[Show abstract][Hide abstract] ABSTRACT: Acute lung injury (ALI) presents high mortality and morbidity clinically and by far no effective preventive strategy has been established. Extract of Ginkgo biloba leaves, EGb 761, is a complex mixture that possesses several clinical beneficial effects such as anti-oxidation, anti-inflammation, anti-tumor, and cardioprotective property. With EGb 761 pretreatment, both lipopolysaccharide (LPS)-induced protein leakage and neutrophil infiltration, and LPS-induced inflammatory responses including increased myeloperoxidase (MPO) activity, lipid peroxidation, and metalloproteinase (MMP)-9 activity, were inhibited; LPS-suppressed activation of antioxidative enzymes (AOE) were reversed; and not only the phosphorylation of NF-κB but also the degradation of its inhibitor, IκB, were suppressed. These results suggested that the protection mechanism of EGb 761 is by inhibition of NFκB activation, possibly via the up-regulation of antioxidative enzymes. More studies are needed to further evaluate whether EGb 761 is a suitable candidate as an effective dietary strategy to reduce the incidence of endotoxin-induced ALI.
No preview · Article · Dec 2012 · Phytomedicine: international journal of phytotherapy and phytopharmacology
[Show abstract][Hide abstract] ABSTRACT: Aim: Bisphenol A-glycidyl-methacrylate (BisGMA), a dental composite resin and dentin bonding agent, might prompt inflammatory effects to adjacent tissues. Macrophages are a major cellular component of the inflammatory sites. Little is known about the mechanisms of BisGMA on macrophages activation. The aim of this study was to evaluate BisGMA on proinflammatory mediators generation of murine macrophage RAW264.7 cells. Methods: IL-1β and IL-6 were analyzed by enzyme-linked immunosorbent assay. Nitric oxide, extracellular superoxide anion, and intracellular reaction oxygen species were measured by Griess assay, ferricytochrome c, and 2',7'-dichlorofluorescein assay, respectively. Expression of iNOS, p-p65, IκB, and p-Akt was analyzed by Western blotting. Results: BisGMA augmented the generation of IL-1β, IL-6, nitric oxide and the expression of iNOS in a time- and dose-dependent manner (p<0.05). BisGMA enhanced the generation of intracellular and extracellular ROS in a dose-dependent manner (p<0.05). The levels of p65 phosphorylation, IκB degradation, and Akt phosphorylation were found to be increased in a time- and dose-dependent manner (p<0.05). Conclusions: These results indicate that BisGMA could induce nitric oxide, ROS, and inflammatory cytokines in macrophages. In addition, BisGMA may active macrophage via NF-κB activation, IκB degradation, and p-Akt activation.
No preview · Article · Aug 2012 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
[Show abstract][Hide abstract] ABSTRACT: The reversion-inducing-cysteine-rich protein with Kazal motifs (RECK) down-regulation has been confirmed in numerous human cancers and is clinically associated with metastasis. This study investigates the potential associations of RECK single-nucleotide polymorphisms (SNPs) with hepatocellular carcinoma (HCC) susceptibility and its clinicopathologic characteristics.
A total of 135 HCC cancer patients and 501 cancer-free controls were analyzed for four RECK SNPs (rs10814325, rs16932912, rs11788747, and rs10972727) using real-time PCR and PCR-RFLP genotyping analysis. After adjusting for other co-variants, the individuals carrying RECK promoter rs10814325 inheriting at least one C allele had a 1.85-fold [95% confidence interval (CI), 1.03-3.36] risk of developing HCC compared to TT wild type carriers. The HCC patients, who carried rs11788747 with at least one G allele, had a higher distant metastasis risk than wild type probands.
RECK gene polymorphisms might be a risk factor increasing HCC susceptibility and distant metastasis in Taiwan.
[Show abstract][Hide abstract] ABSTRACT: Acute lung injury (ALI), instilled by lipopolysaccharide (LPS), is a severe illness with excessive mortality and has no specific treatment strategy. Luteolin is an anti-inflammatory flavonoid and widely distributed in the plants. Pretreatment with luteolin inhibited LPS-induced histological changes of ALI and lung tissue edema. In addition, LPS-induced inflammatory responses, including increased vascular permeability, tumor necrosis factor (TNF)-α and interleukin (IL)-6 production, and expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), were also reduced by luteolin in a concentration-dependent manner. Furthermore, luteolin suppressed activation of NFκB and its upstream molecular factor, Akt. These results suggest that the protection mechanism of luteolin is by inhibition of NFκB activation possibly via Akt.
Full-text · Article · Jan 2012 · Evidence-based Complementary and Alternative Medicine
[Show abstract][Hide abstract] ABSTRACT: Hepatocellular carcinoma (HCC) is one of the most frequent malignant neoplasms worldwide, and the second leading cause of death from cancer in Taiwan. Interleukin-8 (IL-8) is an angiogenic chemokine with important roles in the development and progression of many human malignancies including HCC. This study investigates the effects of single-nucleotide polymorphisms (SNPs) in the IL-8 gene on the susceptibility and clinicopathological characteristics of HCC.
One hundred thirty-one HCC patients and 340 control subjects were analyzed for four IL-8 SNPs (-251 T/A, +781 C/T, +1633 C/T, and +2767 A/T) using PCR-RFLP genotyping analysis.
After adjusting for other confounders, results show that individuals with the IL-8 +781 T/T polymorphic genotype had a significantly lower risk of developing HCC than those with the wild-type (C/C) genotype (AOR = 0.346; 95% CI: 0.132-0.909). Multiple regression analysis showed that the presence of T/A or A/A at IL-8 -251 may indicate higher potential risk of hepatitis B infection (AOR = 2.847; 95% CI: 1.083-8.656). Additionally, these four IL-8 SNPs did not associate with liver-related clinicopathological markers in serum.
Genetic polymorphism at IL-8 +781 is an important factor in determining susceptibility to HCC in the Taiwanese population.
Full-text · Article · Dec 2011 · Journal of Surgical Oncology
[Show abstract][Hide abstract] ABSTRACT: Hepatocellular carcinoma (HCC) is one of the most frequent malignant neoplasms worldwide, and is the second leading cause of cancer death in Taiwan. E-cadherin is an epithelial cell adhesion molecule, and decreased E-cadherin expression in HCC is associated with a poor prognosis. This study investigates the effects of single nucleotide polymorphisms (SNPs) in the E-cadherin/CDH1 gene promoter on the risk and clinicopathological characteristics of HCC METHODS: 131 HCC patients and 347 controls were recruited for this study. Genetic polymorphisms of CDH1-160 and -347 were analyzed by PCR-RFLP genotyping analysis.
After adjusting for other confounders, results show that individuals with the CDH1-347G/GA or GA/GA polymorphic genotypes had a significantly higher risk of developing HCC than those with the wild-type (G/G) genotype (adjusted odds ratio = 2.477; 95%CI: 1.421-4.319). Furthermore, patients with HCC with at least one mutant A allele of CDH1-160 had a 4.031-fold risk of progressing to stage III or IV.
This study shows that SNPs in CDH1-347 gene are associated with an increased risk of HCC, and at least one mutant A allele of CDH1-160 gene is associated with the development of stage III or IV of HCC in Taiwanese.
No preview · Article · Sep 2011 · Journal of Surgical Oncology
[Show abstract][Hide abstract] ABSTRACT: Chinese hamster ovary (CHO) cells, its lung fibroblasts (V79), and human lymphocytes are routinely used in in vitro cytogenetic assays, which include micronuclei (MN), sister chromatid exchange (SCE), and chromosome aberration (CA) assays. Mitomycin C (MMC), a DNA cross-link alkylating agent, is both an anticancer medicine and a carcinogen. To study the differential representative values of cell types in MMC-treated cytogenetic assays and its upstream factor, cysteine aspartic acid-specific protease (caspase)-3. Among the chosen cell types, lymphocytes expressed the highest sensitivity in all three MMC-induced assays, whereas CHO and V79 showed varied sensitivity in different assays. In MN assay, the sensitivity of CHO is higher than or equal to V79; in SCE assay, the sensitivity of CHO is the same as V79; and in CA assay, the sensitivity of CHO is higher than V79. In-depth analysis of CA revealed that in chromatid breaks and dicentrics formation, lymphocyte was the most sensitive of all and CHO was more sensitive than V79; and in acentrics and interchanges formation, lymphocyte was much more sensitive than the others. Furthermore, we found caspase-3 activity plays an important role in MMC-induced cytogenetic assays, with MMC-induced caspase-3 activity resulting in more sensitivity in lymphocytes than in CHO and V79. Based on these findings, lymphocyte will make a suitable predictive or representative control reference in cytogenetic assays and caspase-3 activity with its high specificity, positive predictive value, and sensitivity.
No preview · Article · Jul 2011 · Toxicology and Industrial Health
[Show abstract][Hide abstract] ABSTRACT: Acute lung injury (ALI) in critically ill patients remains the leading cause of mortality and morbidity. Lipopolysaccharide (LPS) is a key mediator of lung injury. This study investigates the protective effects and mechanisms of luteolin in intratracheal instillation of LPS (100μg)-induced ALI in mice. Pretreatment of mice with 70μmol/kg luteolin significantly restores LPS-induced decrease in oxygen pressure and increase in carbon dioxide in arterial blood. The histopathological study established 70μmol/kg luteolin pretreatment markedly attenuates lung histopathological changes, such as haemorrhaging, interstitial edema, and infiltration of polymorphonuclear neutrophils (PMNs) into the lung parenchyma and alveolar spaces. Sufficient evidence for luteolin (35 and 70μmol/kg) suppresses activation and infiltration of PMNs is obtained in expression of surface marker CD11b and Ly6G on cells in bronchoalveolar lavage fluid (BALF) cells and myeloperoxidase activity in lung tissue. Furthermore, luteolin reduces the activity of catalase and superoxide dismutase, and the level of oxidative damage, and lipid peroxidation, in lung tissue. In addition, the secretion of TNF-α, KC, and ICAM-1 in the BALF after LPS challenge are also inhibited by luteolin. Moreover, luteolin reduced LPS-induced activation of MAPK and NFκB pathways. Therefore, luteolin is a potential protective antagonists for LPS-induced ALI in mice.
No preview · Article · Jul 2011 · Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association
[Show abstract][Hide abstract] ABSTRACT: Early detection of hepatocellular carcinoma (HCC) is seldom available because of the lack of reliable markers. Matrix metalloproteinase (MMP) 14 is a cell surface proteinase that displays a broad spectrum of activity against extracellular matrix components and promotes the invasion/metastasis of cells. MMP14 is overexpressed in HCC, and the level is correlated with poor overall survival. The purpose of this study was to examine whether the MMP14 gene polymorphisms are associated with the susceptibility and clinicopathological development of HCC.
A total of 135 patients with HCC and 496 healthy control subjects were recruited. Six single nucleotide polymorphisms (SNPs) of MMP14 genes were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) genotyping and haplotype-base analysis.
A significant (p < 0.05) lower risk for HCC was shown in the individuals with MMP14 +6767 G/A and +7096 C/C genotypes compared with those with corresponding wild-type homozygotes; high frequency for anti-hepatitis C virus and cirrhosis positive were shown in the HCC patients with MMP14 +7096 TC/CC genotype after adjusting for other confounding factors. The distribution frequency of -165 T: +221 T: +6727 C: +6767 G: +7096 T: +8153 G haplotype and diplotype was significantly higher in the HCC patients than healthy control subjects.
The +6767 and +7096 polymorphic genotypes and haplotype -165 T: +221 T: +6727 C: +6767 G: +7096 T: +8153 G of MMP14 gene might contribute to the prediction of susceptibility and pathological development to HCC.
Full-text · Article · Feb 2011 · Annals of Surgical Oncology
[Show abstract][Hide abstract] ABSTRACT: Heat shock protein 47 (HSP47) is a product of CBP2 gene located at chromosome 11q13.5, a region frequently amplified in human cancers. Areca quid chewing is a major risk factor of oral squamous cell carcinoma (OSCC). The aim of this study was to compare HSP47 expression in normal human oral epithelium and OSCC and further to explore the potential mechanisms that may lead to induce HSP47 expression.
Thirty-two OSCC specimens and ten normal oral tissue biopsy samples without areca quid chewing were analyzed by immunohistochemistry. The oral epithelial cell line OC2 cells were challenged with arecoline, a major areca nut alkaloid, by using Western blot analysis. Furthermore, glutathione precursor N-acetyl-l-cysteine (NAC), extracellular signal-regulated protein kinase (ERK) inhibitor PD98059, phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002, cyclooxygenase-2 inhibitor NS-398, and tyrosine kinase inhibitor herbimycin A were added to find the possible regulatory mechanisms.
HSP47 expression was significantly higher in OSCC specimens than normal epithelium (P<0.05). No significant difference in HSP47 expression was observed with respect to age, sex, T category, stage, and differentiation (P>0.05). The lower HSP47 expression was associated with lymph node metastasis (P=0.015). Arecoline was found to elevate HSP47 expression in a dose- and time-dependent manner (P<0.05). The addition of NAC, PD98059, LY294002, NS398, and herbimycin A markedly inhibited the arecoline-induced HSP47 expression (P<0.05).
Our findings demonstrated that HSP47 expression is significantly upregulated in areca quid chewing-associated OSCCs. HSP47 could be used clinically as a marker for lymph node metastasis of oral carcinogenesis. In addition, arecoline-induced HSP47 expression was downregulated by NAC, PD98059, LY294002, NS398, and herbimycin A.
No preview · Article · Dec 2010 · Journal of Oral Pathology and Medicine
[Show abstract][Hide abstract] ABSTRACT: To investigate whether luteolin, the major polyphenolic components of Lonicera japonica, has beneficial effects against lipopolysaccharide (LPS)-induced acute lung injury (ALI) and to determine whether the protective mechanism involves anti-inflammatory effects on neutrophils.
ALI was induced with intratracheal instillation of LPS in mice. The level of ALI was determined by measuring the cell count and protein content in bronchoalveolar lavage (BAL) fluid. Neutrophils were stimulated with formyl-Met-Leu-Phe (fMLP) or LPS in vitro. Chemotaxis and superoxide anion generation were measured to evaluate neutrophil activation. The potential involvement of intracellular signaling molecules in regulating neutrophil activation was analyzed by using Western blot.
LPS induced ALI in mice, as evidenced with leukocyte infiltration and protein leakage into the lungs. Luteolin attenuated LPS-induced leukocyte infiltration and protein extravasation. In cell studies, luteolin attenuated the fMLP-induced neutrophil chemotaxis and respiratory burst (IC(50) 0.2+/-0.1 micromol/L and 2.2+/-0.8 micromol/L, respectively), but had a negligible effect on superoxide anion generation during phorbol myristate acetate stimulation. Furthermore luteolin effectively blocked MAPK/ERK kinase 1/2 (MEK), extracellular signal-regulated kinase (ERK), and Akt phosphorylation in fMLP- and LPS-stimulated neutrophils.
These results indicate that luteolin has beneficial effects against LPS-induced ALI in mice, and the attenuation of neutrophil chemotaxis and respiratory burst by luteolin involves the blockade of MEK-, ERK-, and Akt-related signaling cascades.
[Show abstract][Hide abstract] ABSTRACT: Three-dimensional computed tomography (3D-CT) not only allows accurate preoperative delineation of the lesions but also provides precise pathomechanic diagnosis for planning the most effective treatment to avoid respiratory compromise. In a 10-month-old baby girl, who was ventilator-dependent after successful correction of double outlet right ventricle (DORV), flexible fiberoptic bronchoscopy (FFB) revealed the new formation of postoperative airway obstruction over the right main bronchus (RMB) and obstructed right tracheal bronchus (RTB). 3D-CT demonstrated tracheobronchial obstruction (TBO) was caused by the dilated ascending aorta (AAo) and right pulmonary artery (RPA). Sequential treatments including artery pexy of AAo and RPA and balloon dilatation (BD) of the stenotic RTB and RMB had successfully restored the airway patency. The patient was successfully weaned from ventilator 2 days after treatments and has shown no respiratory difficulty thus far. Thus, the impact of preoperative 3D-CT on planning treatment cannot be emphasized.
No preview · Article · Jul 2010 · Pediatric Pulmonology
[Show abstract][Hide abstract] ABSTRACT: 9-Fluorenone (9F), the aromatic photosensitizer, is widely used as an initiator in visible-light (VL) cured resin systems. There is growing concern that 9F may produce genetic damage by inducing mutation. In this study, 9F in the presence or absence of reducing agent N,N-dimethyl-p-toluidine (DMT) with or without VL irradiation was analyzed for the induction of chromosomal aberrations indicated by micronuclei (MN) induced in CHO cells. Our data demonstrated that a dose-related increase in the frequency of MN and prolonged cell cycles in 9F with or without DMT in the presence or absence of VL irradiation (p < 0.05). The rank orders with respect to genotoxicity and cytotoxicity were found to be as follows: 9F/DMT +VL > 9F/DMT = 9F + VL > 9F. To determine whether oxidative stress could modulate MN induced by 9F/DMT with or without VL irradiation in CHO cells, cells were pretreated with N-acetyl-L-cysteine (NAC), ascorbic acid, and alpha-tocopherol. The pretreatment with antioxidants could diminish not only the prolonged cell cycle but also the decreased frequency of MN which is induced by 9F with or without DMT in the presence or absence of VL irradiation in CHO cells (p < 0.05). Our findings provide the evidences for the induction of MN by 9F in the presence or absence of DMT with or without VL irradiation in CHO cells, indicating clastogenic activity of 9F/DMT in vitro. These antioxidants act as the antagonists against the genotoxicity and cytotoxicity of 9F/DMT. Thus, leaching photoinitiator and reducing agent might be contributing the sources of oxidative stress.
No preview · Article · Jan 2008 · Journal of Biomedical Materials Research Part B Applied Biomaterials
[Show abstract][Hide abstract] ABSTRACT: Camphorquinone (CQ) is widely used as an initiator in modern visible-light (VL) cured resin systems. CQ is also characterized as a potential allergenic compound. To date, there is growing concern that CQ may produce genetic damage by inducing mutation. In this study, CQ in the presence of reducing agent N,N-dimethyl-p-toluidine (DMT) with or without VL irradiation was analyzed for the induction of chromosomal aberrations indicated by micronuclei (MN) induced in CHO cells. Our data demonstrated that an increase in the numbers of MN was observed with CQ/DMT with or without VL irradiation (p < 0.05). Significant prolongation of cell cycles was observed by the treatment with CQ/DMT with or without VL irradiation (p < 0.05). In addition, VL irradiated CQ/DMT was found to exhibit significantly genotoxic and cytotoxic effects as compared with CQ/DMT alone (p < 0.05). Furthermore, to determine whether oxidative stress could modulate the MN induced by CQ/DMT with or without VL irradiation in CHO cells, cells were pre-treated with various antioxidants 10 mM N-acetyl-L-cysteine (NAC), 2 mM ascorbic acid, and 2 mM alpha-tocopherol. The pre-treatment with antioxidants could antagonize not only the increased MN cells but also the prolonged cell cycle induced by CQ/DMT with or without VL irradiation in CHO cells (p < 0.05). Our findings provide the evidences for the induction of MN by CQ/DMT employing mammalian test system, indicating clastogenic activity of CQ/DMT with or without VL irradiation in vitro. In addition, VL irradiated CQ/DMT exhibits higher genotoxic and cytotoxic effects than CQ/DMT alone. Moreover, NAC, ascorbic acid, and alpha-tocopherol act as the antagonists against the genotoxicity and cytotoxicity of CQ/DMT with or without VL irradiation.
No preview · Article · Jul 2007 · Journal of Biomedical Materials Research Part B Applied Biomaterials