No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Long-Term Treatment with a "Yang-Invigorating" Chinese Herbal Formula, Wu-Zi-Yan-Zong-Wan, Reduces Mortality and Liver Oxidative Damage in Chronic Alcohol-Intoxicated Rats
Abstract
Long-term alcohol consumption has been reported to increase oxidative stress in multiple organs and accelerate the aging process. A previous study in our laboratory has shown that Wu-Zi-Yan-Zong-Wan (WZ), a "Yang-invigorating" Chinese herbal formula, protected against ethanol-induced toxicity in HepG2 cells transfected to express human CYP2E1, presumably by enhancing mitochondrial antioxidant status and functional ability. The present study aims to investigate whether WZ extract treatment can afford protection against chronic ethanol-induced oxidative stress (a major risk factor of aging) and mortality in rats. The effect of the extract (1.8 g, 4.5 g, and 9 g raw materials/kg per day) on chronic ethanol hepatotoxicity was investigated in rats receiving steady intragastric infusion of ethanol-containing liquid diet. The results showed that long-term (42 days) herbal co-treatment protected against chronic ethanol-induced mortality and hepatotoxicity and in rats, as evidenced by decreased plasma transaminases activities. The extract also suppressed the pathological development of fatty liver, as assessed by histopathological examination and the ratio of liver weight to body weight. The hepatoprotection afforded by the extract was associated with decreases in the extents of reactive oxygen species production, lipid peroxidation, and oxidative modification of proteins, as well as the reversal of altered mitochondrial reduced glutathione level. The results suggest that the suppressive effect of WZ on chronic ethanol-induced oxidative stress and mortality may be attributed to the antioxidant action, particularly in mitochondria.
... Traditional Chinese medicines, particularly compound medicines (known as prescriptions or Fu Fangs in Chinese), have garnered significant global interest for their superior efficacy and safety profiles in the prevention and treatment of various diseases (Cheung, 2011). Current research indicates a growing interest in utilizing traditional herbal formulae as novel therapeutic approaches for treating ALD due to their efficacy, minimal adverse effects, and costeffectiveness (Chen et al., 2010;Mo et al., 2020;Fang et al., 2023). Among these formulae, maintaining the equilibrium of Yin and Yang is considered a fundamental strategy for restoring health. ...
... Alcohol consumption is a major global issue for liver damage, with a growing focus on research into preventing and treating alcohol-related liver injury using Chinese herbal medicines (Chen et al., 2010;Feng et al., 2019;Foghis et al., 2023). This study presents the initial evidence that XZTZ, a modified version of the historic prescription 'Golden Chamber • Phlegm and Cough Disease', alleviated alcohol-induced liver injury, oxidative stress in the liver, and liver inflammation in C57BL/6J mice in a dose-dependent manner (Figure 6). ...
This study aimed to evaluate the protective role and potential mechanisms of Xie Zhuo Tiao Zhi decoction (XZTZ) on alcohol-associated liver disease (ALD). XZTZ significantly alleviated alcohol-induced liver dysfunction, based on histological examinations and biochemical parameters after 4-week administration. Mechanically, alcohol-stimulated hepatic oxidative stress was ameliorated by XZTZ, accompanied by the improvement of Nrf2/Keap1 expression and alcohol-activated phosphorylation of pro-inflammatory transcription factors, including JNK, P38, P65, and IκBα, were rescued by XZTZ. In conclusion, XZTZ demonstrates potential in alleviating alcohol-induced liver injury, oxidative stress, and inflammation possibly through modulation of Nrf2/Keap1 and MAPKs/NF-κB signaling pathways, suggesting its potential as a therapeutic option for patients with alcoholic liver disease.
... In addition, recent studies have shown that Cuscuta chinensis Lam. and Lycium chinense act as antioxidants in maintaining sperm quality [35,36]. Wu-Zi-Yan-Zong-Wan, which contains Cuscuta chinensis Lam. and Lycium chinense, has a protective effect against oxidative damage of mitochondrial DNA (mtDNA) in aged men [37,38]. Moreover, studies in animals showed that Wu-Zi-Yan-Zong-Wan exhibited protective effects against ionizing radiation-induced testicular damage, which may have been related to its antioxidant abilities [39]. ...
Poor sperm quality is one of the main factors of male infertility. Traditional Chinese Medicine (TCM) has been used frequently in clinical practice in many countries to treat a wide array of infertile problems. To further understand the effects of TCM on semen quality, we retrospectively enrolled patients with male infertility and poor semen quality at the Tainan Municipal Hospital in Taiwan between 2013 and 2016. Semen quality analysis in accordance with the WHO criteria is an essential step in the evaluation of male fertility status. Associations between the semen parameters and body mass index, smoking status, alcohol use, duration of infertility, and age were also analyzed. A total of 126 male infertility patients with abnormal semen analysis were included in this study: 50 TCM users and 13 TCM non-users. The basic characteristics of the two groups were not significantly different. TCM users account for 92.5% of the total semen improvement subjects. In conclusion, TCM supplementation may have a beneficial role as improving sperm quality for infertility patients.
... In addition, Wu-Zi-Yan-Zhong-Wan (WZ), a Chinese herbal formula containing five herbs, namely, Fructus Lycii, Semen Cuscutae, Fructus Rubi, Semen Plantaginis and Fructus Schisandrae, is prescribed for treating "Yang deficiency" in TCM. Studies showed that WZ decreased the extent of ethanol-induced ROS production and lipid peroxidation as well as prevented ethanol-induced decreases in cellular/mitochondrial GSH levels and mitochondrial membrane potential in CYP2E1 cDNA-transfected human HepG2 (E47) cells [41] and chronic ethanol-intoxicated rats [42]. Taken together, both cell-based and animal studies provide convincing evidence to support the role of Yang tonic herbs/formulae in protecting the body against oxidantinduced injury, presumably by up-regulating cellular/mitochondrial antioxidant defense components in a tissue non-specific manner. ...
Chinese tonic herbs are generally classified into Yin and Yang categories based on their health-promoting action. Emerging evidence has suggested that in addition to up-regulating mitochondrial functional status, Yang tonic herbs also enhance cellular/mitochondrial antioxidant capacity, and may thus prevent age-related diseases and prolong the healthy part of lifespan (i.e. healthspan). The proposed biochemical mechanism underlying the antioxidant action of Yang tonic herbs involves a sustained and low level of mitochondrial reactive oxygen species production, which is secondary to the increased activity of the electron transport chain, with the possible involvement of mitochondrial uncoupling. “Yang invigoration” improves antioxidant defense in the body in the long term and thereby offers a promising prospect for preventing or possibly delaying age-related diseases and the detrimental effects of aging.
... Previous studies in our laboratory have demonstrated the ability of Yang tonic herbs to increase mitochondrial ATP-GC, which is associated with an increased activity of the mitochondrial electron transport system [13]. In addition to upregulating mitochondrial functional capacity, Yang tonic herbs/formulas have also been shown to enhance cellular/mitochondrial antioxidant status [14] and also decrease mitochondrial coupling efficiency [15], thereby protecting against oxidant injury in various tissues of rats [16,17]. ...
Mitochondrial decay is considered to be a major contributor to aging-related diseases, including neurodegenerative diseases, cardiovascular disorders, and certain metabolic diseases. Therefore, the maintenance of mitochondrial functional capacity and antioxidant status should play an essential role in preventive health. Herba Cynomorii, which is one of the most potent "Yang-invigorating" Chinese tonic herbs, was found to increase mitochondrial ATP generation capacity (ATP-GC) in rat hearts ex vivo. In the present study, we demonstrated that HCY2, an active fraction of Herba Cynomorii, and its major ingredient ursolic acid (UA) could protect against hypoxia/reoxygenation-induced cell apoptosis in H9c2 cells in vitro and also against ischemia/reperfusion-induced injury in rat hearts ex vivo. The cardioprotection was associated with an increase in ATP-GC and an enhancement of glutathione redox cycling. The results suggest that UA may be one of the active ingredients responsible for the cardioprotection afforded by Herba Cynomorii, and this effect may be mediated, at least in part, by enhancement of mitochondrial functional capacity and antioxidant status, possibly through the induction of mitochondrial uncoupling.
Aging-associated diseases are often incurable or not effectively managed by modern medicine. Preventive health has become a trend in aging societies throughout the world. Chinese medicine (CM), which adopts a holistic approach in the prevention and/or treatment of diseases, may provide a rational basis for the development of herbal health products for use in health promotion. According to CM theory, Chinese tonifying herbs are divided into four functional categories: Yang-invigorating, Yin-nourishing, Qi-invigorating, and Blood-enriching. A growing body of experimental evidence has accumulated establishing the pharmacological basis of the actions of active components isolated from Chinese tonifying herbs in ameliorating pathological manifestations of various aging-associated diseases. While pharmacological studies have demonstrated the beneficial actions of these active components, the long-term administration of a single compound for preventive health is not considered optimal in the practice of CM. To optimize the efficacy and ensure safety in preventive health, herbal formulations, which contain a combination of tonifying herbs according to the principles of CM, are much preferred for the development of herbal health products.
Type-1, type-2, and gestational/embryonic diabetes are all damaging and impair the nervous system. All three forms of diabetes cause oxidative stress, apoptosis, and neuropathy. In type-1 and type-2 diabetes (T2D), oxidative stress and apoptosis involve excessive release of glutamate, activation of N-methyl-d-aspartate (NMDA) receptors, increased cytoplasmic Ca+2 levels, and complex signaling pathways leading to apoptosis. Neuropathy has also been associated with a reduction in a number of neurotrophic factors, including brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), and the use of exogenous BDNF and GDNF in ameliorating type-1 and type-2 diabetic symptoms has been reported. While several regions of the brain are affected, the hypothalamus and hippocampus are key areas of neuropathy. While less understood, gestational diabetes also causes oxidative stress and apoptosis within fetal brains and embryonic hyperglycemia is associated with hyperhomocysteinemia and subsequent apoptosis. Elevated embryonic homocysteine (HoCys) levels promote membrane lipid peroxidation, apoptosis, and are teratogenic in chicks. Data presented in this review indicate that embryonic hyperglycemia inhibits both the remethylation pathway, which is largely dependent on 5-methyltetrahydrofolate levels, and the transsulfuration pathway, which removes HoCys ultimately to α-ketobutyrate, glutathione, and taurine. HoCys is of interest because HoCys is both an agonist and antagonist of NMDA receptors.
Lipid peroxidation is observed during both necrosis and apoptosis [1–4]. The ethanol (EtOH)-induced synthesis of reactive oxygen species (ROS), lipid peroxidation, mitochondria dysfunction, and oxidative stress has been demonstrated in adult rat brains [5, 6], neuronal cell cultures [7], glial cell cultures [6–8], embryonic chick brains [9–13], and rat placental tissues [14]. EtOH-induced oxidative stress has been well documented in alcohol-induced: liver disease [15–19], muscle disease [20], kidney alterations [21], erosion and alterations of digestive tract mucosa [22, 23], and pancreatitis [24]. Since the author last reviewed EtOH-induced lipid peroxidation in 2004 [25], this chapter will primarily concentrate on papers published after 2004.
In TEFL, it is often stated that communication presupposes comprehension. The main purpose of readability studies is thus to measure the comprehensibility of a piece of writing. In this regard, different readability measures were initially devised to help educators select passages suitable for both children and adults. However, readability formulas can certainly be extremely helpful in the realm of EFL reading. They were originally designed to assess the suitability of books for students at particular grade levels or ages. Nevertheless, they can be used as basic tools in determining certain crucial EFL text-characteristics instrumental in the skill of reading and its related issues. The aim of the present paper is to familiarize the readers with the most frequently used readability formulas as well as the pros and cons views toward the use of such formulas. Of course, this part mostly illustrates studies done on readability formulas with the results obtained. The main objective of this part is to help readers to become familiar with the background of the formulas, the theory on which they stand, what they are good for and what they are not with regard to a number of studies cited in this section.
Alzheimer disease (AD) is a progressive neurodegenerative disorder whose clinical manifestations appear in old age. The sporadic nature of 90% of AD cases, the differential susceptibility to and course of the illness, as well as the late age onset of the disease suggest that epigenetic and environmental components play a role in the etiology of late-onset AD. Animal exposure studies demonstrated that AD may begin early in life and may involve an interplay between the environment, epigenetics, and oxidative stress. Early life exposure of rodents and primates to the xenobiotic metal lead (Pb) enhanced the expression of genes associated with AD, repressed the expression of others, and increased the burden of oxidative DNA damage in the aged brain. Epigenetic mechanisms that control gene expression and promote the accumulation of oxidative DNA damage are mediated through alterations in the methylation or oxidation of CpG dinucleotides. We found that environmental influences occurring during brain development inhibit DNA-methyltransferases, thus hypomethylating promoters of genes associated with AD such as the beta-amyloid precursor protein (APP). This early life imprint was sustained and triggered later in life to increase the levels of APP and amyloid-beta (Abeta). Increased Abeta levels promoted the production of reactive oxygen species, which damage DNA and accelerate neurodegenerative events. Whereas AD-associated genes were overexpressed late in life, others were repressed, suggesting that these early life perturbations result in hypomethylation as well as hypermethylation of genes. The hypermethylated genes are rendered susceptible to Abeta-enhanced oxidative DNA damage because methylcytosines restrict repair of adjacent hydroxyguanosines. Although the conditions leading to early life hypo- or hypermethylation of specific genes are not known, these changes can have an impact on gene expression and imprint susceptibility to oxidative DNA damage in the aged brain.
The continuous intragastric enteral feeding protocol in the rat was a major development in alcohol-induced liver injury (ALI) research. Much of what has been learned to date involves inhibitors or nutritional manipulations that may not be specific. Knockout technology avoids these potential problems. Therefore, we used long-term intragastric cannulation in mice to study early ALI. Reactive oxygen species are involved in mechanisms of early ALI; however, their key source remains unclear. Cytochrome P-450 (CYP)2E1 is induced predominantly in hepatocytes by ethanol and could be one source of reactive oxygen species leading to liver injury. We aimed to determine if CYP2E1 was involved in ALI by adapting the enteral alcohol (EA) feeding model to CYP2E1 knockout (-/-) mice. Female CYP2E1 wild-type (+/+) or -/- mice were given a high-fat liquid diet with either ethanol or isocaloric maltose-dextrin as control continuously for 4 wk. All mice gained weight steadily over 4 wk, and there were no significant differences between groups. There were also no differences in ethanol elimination rates between CYP2E1 +/+ and -/- mice after acute ethanol administration to naive mice or mice receiving EA for 4 wk. However, EA stimulated rates 1.4-fold in both groups. EA elevated serum aspartate aminotransferase levels threefold to similar levels over control in both CYP2E1 +/+ and -/- mice. Liver histology was normal in control groups. In contrast, mice given ethanol developed mild steatosis, slight inflammation, and necrosis; however, there were no differences between the CYP2E1 +/+ and -/- groups. Chronic EA induced other CYP families (CYP3A, CYP2A12, CYP1A, and CYP2B) to the same extent in CYP2E1 +/+ and -/- mice. Furthermore, POBN radical adducts were also similar in both groups. Data presented here are consistent with the hypothesis that oxidants from CYP2E1 play only a small role in mechanisms of early ALI in mice. Moreover, this new mouse model illustrates the utility of knockout technology in ALI research.
In North America, liver disease due to alcohol consumption is an important cause of death in adults, although its pathogenesis remains obscure. Despite the fact that resident hepatic macrophages are known to contribute to early alcohol-induced liver injury via oxidative stress, the exact source of free radicals has remained a mystery. To test the hypothesis that NADPH oxidase is the major source of oxidants due to ethanol, we used p47(phox) knockout mice, which lack a critical subunit of this major source of reactive oxygen species in activated phagocytes. Mice were treated with ethanol chronically, using a Tsukamoto-French protocol, for 4 weeks. In wild-type mice, ethanol caused severe liver injury via a mechanism involving gut-derived endotoxin, CD14 receptor, production of electron spin resonance-detectable free radicals, activation of the transcription factor NF-kappaB, and release of cytotoxic TNF-alpha from activated Kupffer cells. In NADPH oxidase-deficient mice, neither an increase in free radical production, activation of NF-kappaB, an increase in TNF-alpha mRNA, nor liver pathology was observed. These data strongly support the hypothesis that free radicals from NADPH oxidase in hepatic Kupffer cells play a predominant role in the pathogenesis of early alcohol-induced hepatitis by activating NF-kappaB, which activates production of cytotoxic TNF-alpha.
The goal of this study was to compare brain volumes of alcoholic and nonalcoholic men and women and determine if the magnitudes of differences in brain volumes between alcoholic women and nonalcoholic women are greater than the magnitudes of the differences between alcoholic men and nonalcoholic men.
The study group included 118 subjects: 79 inpatients 30-60 years of age who were alcohol dependent but had no clinically apparent cognitive impairment or medical illness (43 men and 36 women) and 39 healthy comparison subjects of similar age who were not alcoholic (20 men and 19 women). The volume of intracranial contents was segmented into gray matter, white matter, sulcal CSF, and ventricular CSF from a T(1)-weighted magnetic resonance image obtained after the alcoholic subjects had attained 3 weeks of sobriety.
Alcoholic women had significantly smaller volumes of gray and white matter as well as greater volumes of sulcal and ventricular CSF than nonalcoholic women. The differences in gray and white matter volumes between alcoholic and nonalcoholic men were significant, but the significance of these differences was of a smaller magnitude than the significance of the differences between alcoholic and nonalcoholic women. Direct comparisons of alcoholic men and women showed that the proportion of intracranial contents occupied by gray matter was smaller in alcoholic women than in alcoholic men. The magnitudes of differences in brain volumes adjusted for intracranial size between alcoholic women and nonalcoholic women were greater than the magnitudes of the adjusted differences between alcoholic men and nonalcoholic men.
These results are consistent with greater sensitivity to alcohol neurotoxicity among women.
Ancient traditional Chinese medicine (TCM) has effectively relied on the theory of yin-yang balance in diagnoses and treatments of diseases and disorders for more than 2000 years. However, in eastern society, yin-yang is regarded as an incomprehensible ideology without definite physical meaning. Consequently, the yin-yang balance in medicine has not been studied by modern scientific means. In the western world, yin-yang balance is often misunderstood as a religious belief or a principle of lifestyle. Herein, we attempted to define the physical meaning of yin-yang in TCM by correlating it with biochemical processes. We propose that yin-yang balance is antioxidation-oxidation balance with yin representing antioxidation and yang as oxidation. Our proposal is partially supported by the fact that the yin-tonic traditional Chinese herbs have, on average, about six times more antioxidant activity and polyphenolic contents than the yang-tonic herbs. Our hypothesis opens an avenue to systematically study the yin-yang balance and its health implications with the use of modern biochemical tools.
Oxidative stress, an imbalance toward the pro-oxidant side of the pro-oxidant/antioxidant homeostasis, occurs in several human diseases. Among these diseases are those in which high levels of protein carbonyl (CO) groups have been observed, including Alzheimer's disease (AD), rheumatoid arthritis, diabetes, sepsis, chronic renal failure, and respiratory distress syndrome. What relationships might be among high level of protein CO groups, oxidative stress, and diseases remain uncertain.The usage of protein CO groups as biomarkers of oxidative stress has some advantages in comparison with the measurement of other oxidation products because of the relative early formation and the relative stability of carbonylated proteins. Most of the assays for detection of protein CO groups involve derivatisation of the carbonyl group with 2,4-dinitrophenylhydrazine (DNPH), which leads to formation of a stable dinitrophenyl (DNP) hydrazone product. This then can be detected by various means, such as spectrophotometric assay, enzyme-linked immunosorbent assay (ELISA), and one-dimensional or two-dimensional electrophoresis followed by Western blot immunoassay. At present, the measurement of protein CO groups after their derivatisation with DNPH is the most widely utilized measure of protein oxidation.
The practice of traditional Chinese medicine (TCM) always emphasizes the prevention of diseases and delaying the onset of senility. In this regard, the maintenance of a balance of Yin and Yang-two opposing components involved in life activities as exemplified by the antagonistic action of the sympathetic and parasympathetic nervous systems-is essential in achieving a healthy condition. Previous studies have shown that long-term treatment with a Yang-invigorating Chinese herbal formula (VI-28) could increase red cell CuZn-superoxide dismutase (SOD) activity in male human subjects. In the present study, we examined the effects of chronic VI-28 treatment (80 and 240 mg/kg/day for 30 days) on red cell CuZn-SOD activity as well as mitochondrial functional ability and antioxidant components in various tissues of male and female rats. The results indicated that VI-28 treatment increased red cell CuZn-SOD activity as well as mitochondrial ATP generation capacity, reduced glutathione and alpha-tocopherol levels, and Mn-SOD activity in brain, heart, liver, and skeletal muscle tissues in both male and female rats to varying extents. The VI-28?induced increase in mitochondrial antioxidant capacity in various tissues was evidenced by the significant reduction in the extent of reactive oxygen species generation assessed by in vitro measurement. The red cell CuZn-SOD activities correlated positively with tissue mitochondrial antioxidant component levels/activity. The beneficial effect of VI-28 treatment on mitochondrial functional ability and antioxidant capacity may have clinical implications in the prevention of age-related diseases.
We have previously shown that the treatment with diallyl sulfide (DAS) and phenylethyl isothiocyanate (PIC) of rats receiving ethanol in the alcohol tube-feeding model effectively suppressed the induction of cytochrome P4502E1 (CYP2E1) by ethanol. Here we report that rat treatment with DAS and PIC significantly decreased the trapping of hydroxyethyl free radicals in liver microsomes incubated in vitro with ethanol. Furthermore, these inhibitors also greatly reduced the production of hydroxyethyl radical-derived epitopes detectable in vivo in the liver of ethanol-fed rats. The action of DAS and PIC on the formation of hydroxyethyl radicals paralleled their inhibitory effect on lipid peroxidation as monitored using, respectively, liver malonildialdehyde (MDA) and plasma lipid hydroperoxide levels as well as by the titers of antibodies versus MDA adducts to proteins. Thus, these results indicated a link between the induction of CYP2E1 by ethanol, the formation of hydroxyethyl radicals and the stimulation of lipid peroxidation. The pathological scores in the livers of rats fed with ethanol plus or minus DAS and PIC also correlated with levels of hydroxyethyl radical-derived epitopes. Rats fed intragastrically with ethanol developed antibodies and the formation of these antibodies was greatly reduced by DAS and PIC. Taken together these results suggest that CYP2E1 plays an important role in the generation of hydroxyethyl radicals during chronic alcohol feeding and that ethanol-derived free radicals might play a role in the onset of liver injury in this model of alcohol administration. (Hepatology 1996 Jan;23(1):155-63)
This study involved an evaluation of two versions of the “premature aging” theory of chronic alcoholism: the accelerated aging and increased vumerabHty versions. The major dependent measures used were the tests included in Reitan's brain age quotient (BAO), a series of neuropsychological tests known to be sensitive to the effects of alcoholism and aging. Subjects were 40 chronic alcoholic inpatients and 40 matched controls, divided into age groups by; decade, ranging from the 30s to the 60s. It was proposed that an j interaction between age and presence or absence of alcoholism, with BAO test differences between alcoholics and controls widening as age increases, would support the increased vulnerability version, while the absence of such aw interaction would support the accel-] erated aging version. The results dearty favored the accelerated aging version, with merited BAO test differences between alcoholics, and controls appearing even in the 30-year-old groups. It was concluded that chronic ateohoftcs tend to perform at levels found for nonalconoiics 10 years their senior, but the discrepancy between, alcoholics and nonalcohoics does not increase with age.
A battery of cognitive tests was administered to groups of younger (34–49) and older (50–59) alcoholics and nonalcoholic control subjects. Regardless of age, alcoholics were found to be impaired on essentially all measures of learning and memory. The relevance of these findings to the premature-aging hypothesis is discussed.
We had previously hypothesized that linoleic acid (LA) was essential for development of alcoholic induced liver injury in our rat model. Male Wistar rats were fed a nutritionally adequate diet (25% calories as fat) with ethanol (8–17 g/kg/day). The source of fat was tallow (0.7% LA), lard (2.5% LA) or tallow supplemented with linoleic acid (2.5%). Liver damage was followed monthly by obtaining blood for alanine aminotransferase assay and liver biopsy for assessment of morphologic changes. Enzyme and histologic changes (fatty liver, necrosis and inflammation) in the tallow-linoleic acid-ethanol fed animals were more severe than in the lard-ethanol group. The tallow ethanol group did not show any evidence of liver injury. Our results strongly support our hypothesis that LA is essential for development of alcoholic liver disease in our rat model.
Wu-Zi-Yan-Zong-Wan (WZ) is a traditional Chinese herbal formula which is commonly used for treating patients with "Yang deficiency". In the present study, the effect of WZ on ethanol-induced toxicity in CYP2E1 cDNA-transfected HepG2 (E47) cells was investigated.
WZ extract was obtained by extracting the herbal powder with 50% ethanol (v/v, in water) and the effect of the extract on ethanol-induced toxicity was investigated in cultured cells.
The treatment with WZ extract (12.5-200 microg/mL) for 24h dose-dependently protected against ethanol-induced toxicity in E47 cells, as evidenced by the enhanced cell viability and decreased extent of lactate dehydrogeanse leakage. The cytoprotection against ethanol-induced toxicity was associated with decreases in the extents of reactive oxygen species production and lipid peroxidation, as well as increases in mitochondrial reduced glutathione and membrane potential. In addition, WZ extract treatment also suppressed the formation of DNA fragments in ethanol-intoxicated E47 cells.
WZ extract was found to protect against the ethanol-induced toxicity in E47 cells, possibly by virtues of its antioxidant activity.
Alcohol consumption has been identified as an important risk factor for chronic disease and injury. In the first paper in this Series, we quantify the burden of mortality and disease attributable to alcohol, both globally and for ten large countries. We assess alcohol exposure and prevalence of alcohol-use disorders on the basis of reviews of published work. After identification of other major disease categories causally linked to alcohol, we estimate attributable fractions by sex, age, and WHO region. Additionally, we compare social costs of alcohol in selected countries. The net effect of alcohol consumption on health is detrimental, with an estimated 3.8% of all global deaths and 4.6% of global disability-adjusted life-years attributable to alcohol. Disease burden is closely related to average volume of alcohol consumption, and, for every unit of exposure, is strongest in poor people and in those who are marginalised from society. The costs associated with alcohol amount to more than 1% of the gross national product in high-income and middle-income countries, with the costs of social harm constituting a major proportion in addition to health costs. Overall, we conclude that alcohol consumption is one of the major avoidable risk factors, and actions to reduce burden and costs associated with alcohol should be urgently increased.
This review has summarized some of the data supporting a role of ROS and oxidant stress in the genesis of hypertension. There is evidence that hypertensive stimuli, such as high salt and angiotensin II, promote the production of ROS in the brain, the kidney, and the vasculature and that each of these sites contributes either to hypertension or to the untoward sequelae of this disease. Although the NADPH oxidase in these various organs is a predominant source, other enzymes likely contribute to ROS production and signaling in these tissues. A major clinical challenge is that the routinely used antioxidants are ineffective in preventing or treating cardiovascular disease and hypertension. This is likely because these drugs are either ineffective or act in a non-targeted fashion, such that they remove not only injurious ROS Fig. 5. Proposed role of T cells in the genesis of hypertension and the role of the NADPH oxidase in multiple cells/organs in modulating this effect. In this scenario, angiotensin II stimulates an NADPH oxidase in the CVOs of the brain, increasing sympathetic outflow. Sympathetic nerve terminals in lymph nodes activate T cells, and angiotensin II also directly activates T cells. These stimuli also activate expression of homing signals in the vessel and likely the kidney, which attract T cells to these organs. T cells release cytokines that stimulate the vessel and kidney NADPH oxidases, promoting vasoconstriction and sodium retention. SFO, subfornical organ. 630 Harrison & Gongora but also those involved in normal cell signaling. A potentially important and relatively new direction is the concept that inflammatory cells such as T cells contribute to hypertension. Future studies are needed to understand the interaction of T cells with the CNS, the kidney, and the vasculature and how this might be interrupted to provide therapeutic benefit.
Fascination by the mitochondria, “the colonial posterity of migrant prokaryocytes, probably primitive bacteria that swam into ancestral precursors of our eukaryotic cells and stayed there,”1 stems from the above-mentioned nebulous endosymbiotic theory of their origin, as well as from the growing realization of a very special role that they play in the pathogenesis of diverse diseases.
These organelles generate energy primarily in the form of the electrochemical proton gradient (ΔμH+), which fuels ATP production, ion transport, and metabolism.2 Generation of this universal energy currency, ΔμH+, occurs through the series of oxidative reactions conducted by the respiratory chain complexes at the ion-impermeable, almost cholesterol-free inner membrane. Reduced nicotinamide adenine dinucleotide represents the entry point to the complex I (reduced nicotinamide adenine dinucleotide:ubiquinone reductase), whereas the reduced ubiquinol enters the respiratory chain in the complex III (ubiquinol:cytochrome c [cyt-c] reductase) to reduce cyt-c, the electron carrier to the complex IV, cyt-c oxidase. Each of these steps generates ΔμH+ by electrogenic pumping of protons from the mitochondrial matrix to the intermembrane space and is coupled to electron flow, thus generating the electric membrane potential of −180 to −220 mV and a pH gradient of 0.4 to 0.6 U across the inner mitochondrial membrane resulting in the negatively charged matrix side of the membrane and alkaline matrix. Ultimately, accumulated ΔμH+ is converted into the influx of protons into the matrix driving ATP synthesis or protein transport. In addition, these end points are necessary for the execution of 2 major enzymatic metabolic pathways within the mitochondrial matrix: the tricarboxylic acid (TCA) oxidation cycle and the fatty acid β-oxidation pathway. This intricate system fueling cellular functions is as elegant as it is vulnerable: practically every component of the system, from the electron transport chain complexes to the permeability properties of the membranes, is a …
The pathogenesis and progression of alcoholic liver disease (ALD) are associated with free radical injury and oxidative stress, which could be partially attenuated by antioxidants and free radical scavengers. Quercetin, one of the most widely distributed flavonoids in plants, is a natural antioxidant. The hypothesis that quercetin could prevent the ethanol-induced oxidative damage in hepatocytes was investigated. The ethanol-intoxicated (100mM for 8h) rat primary hepatocytes were post-treated (2h), simultaneously treated or pre-treated (2h) with quercetin respectively, while the time-dependent (0.5-8h) and dose-dependent (25-200muM) quercetin pre-treatment were used in the present study. The parameters of lactate dehydrogenase (LDH), aspartate transaminase (AST), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were determined to address the alterations of cell damage and antioxidant state after quercetin intervention. The toxic insult of ethanol to hepatocytes was challenged by quercetin and these parameters almost returned to the level of control group when hepatocytes were pre-treated with quercetin at the dose of 50muM for 2-4h before ethanol exposure. In conclusion, quercetin pre-treatment provided protection against ethanol-induced oxidative stress in hepatocytes and may be used as a new natural drug for the prevention and/or treatment of ALD.
Metabolic syndrome is a collection of cardiometabolic risk factors that includes obesity, insulin resistance, hypertension and dyslipidemia. Although there has been significant debate regarding the criteria and concept of the syndrome, this clustering of risk factors is unequivocally linked to an increased risk of developing type 2 diabetes and cardiovascular disease. Metabolic syndrome is often characterized by oxidative stress, a condition in which an imbalance results between the production and inactivation of reactive oxygen species. Reactive oxygen species can best be described as double-edged swords; while they play an essential role in multiple physiological systems, under conditions of oxidative stress, they contribute to cellular dysfunction. Oxidative stress is thought to play a major role in the pathogenesis of a variety of human diseases, including atherosclerosis, diabetes, hypertension, aging, Alzheimer's disease, kidney disease and cancer. The purpose of this review is to discuss the role of oxidative stress in metabolic syndrome and its major clinical manifestations (namely coronary artery disease, hypertension and diabetes). It will also highlight the effects of lifestyle modification in ameliorating oxidative stress in metabolic syndrome. Discussion will be limited to human data.
"Modern" medicine and pharmacology require an effective medical drug with a single compound for a specific disease. This seams very scientific but usually has unavoidable side effects. For example, the chemical therapy to cancer can totally damage the immunological ability of the patient leading to death early than non-treatment. On the other hand, natural antioxidant drugs not only can cure the disease but also can enhance the immunological ability of the patient leading to healthier though they usually have several compounds or a mixture. For the degenerative disease such as Alzheimer's disease (AD) and Parkinson's disease (PD), natural antioxidant drugs are suitable drugs, because the pathogenesis of these diseases is complex with many targets and pathways. These effects are more evidence when the clinic trial is for long term treatment. The author reviews the studies on the protecting effects of natural antioxidants on neurons in neurodegenerative diseases, especially summarized the results about protective effect of green tea polyphenols on neurons against apoptosis of cellular and animal PD models, and of genestine and nicotine on neurons against A beta-induced apoptosis of hippocampal neuronal and transgenic mouse AD models.
Neuro-cognitive deficits, neuronal injury, and neurodegeneration are well documented in alcoholics, yet the underlying mechanisms remain elusive. Oxidative damage of mitochondria and cellular proteins intertwines with the progression of neuroinflammation and neurological disorders initiated by alcohol abuse. Here, we present the evidence that metabolism of ethanol in primary human neurons by alcohol dehydrogenase (ADH) or cytochrome P450-2E1 (CYP2E1) generates reactive oxygen species (ROS) and nitric oxide (NO) via induction of NADPH/xanthine oxidase (NOX/XOX) and nitric oxide synthase (NOS) in human neurons. The acetaldehyde-mediated increase in NOX, XOX, or NOS activity is regulated as a transcriptional rather than a translational process. Marked increase in the lipid peroxidation product (4-hydroxynonenal) and enhanced ROS generation coincides with decreased neuronal viability and diminished expression of neuronal marker (neurofilaments). Novel quantitative methods of ROS and NO detection help dissect the mechanisms of alcohol-induced neurodegeneration. Uncovering the basic mechanisms of oxidative neuronal injury will serve as the basis for development of new therapies.
Investigated the effects of alcoholism and advanced age on Wechsler Adult Intelligence Scale (WAIS) performance and tested the validity of indices of "organicity" and "mental aging" derived from WAIS scores. The WAIS was administered to three groups of 20 males each: young normal (mean age 31 years), young alcoholic (mean age 33 years), and elderly normal (mean age 71 years. In terms of scaled scores, the young normal group was generally superior to the other groups on Verbal and Performance subtests, and the alcoholic and elderly groups resembled each other more on the Verbal than the Performance subtests. In view of an almost 40-year difference in age between the young alcoholic and the elderly normal Ss, similarities in pattern of performance provided some evidence for the hypothesis of "premature aging" in alcholics.
Very high level oxidative damage to DNA occurs during normal metabolism. In each rat cell the steady-state level of this damage is estimated to be about 10(6) oxidative adducts, and about 10(5) new adducts are formed daily. This endogenous DNA damage appears to be a major contributor to aging and to the degenerative diseases associated with aging such as cancer. The oxidative damage rate in mammalian species with a high metabolic rate, short life span, and high age-specific cancer rate such as rats is much higher than the rate in humans, long-lived mammals with a lower metabolic rate and a lower age-specific cancer rate. It is argued that deficiency of micronutrients that protect against oxidative DNA damage is a major contributor to human cancer. Epidemiological studies, a large body of experimental evidence, and theoretical work on the mechanisms of carcinogenesis point to mitogenesis as a major contributor to cancer. Dividing cells compared to nondividing cells are at an enormously increased risk for mutations in part due to the conversion of DNA adducts to mutations. Mitogenesis also increases the probability of gene amplification and loss of 5-methylcytosine. Dietary interventions that lower mitogenesis, such as calorie restriction, decrease the incidence of cancer.
The precise role of lipid peroxidation in the pathogenesis of alcoholic liver disease is still being debated. To explore the issue, this study was undertaken to investigate the status of lipid peroxidation, antioxidants and prooxidants at two discrete stages of experimental alcoholic liver disease. Male Wistar rats were intragastrically fed a high-fat diet plus ethanol for 5 or 16 wk (the duration that resulted in initiation of centrilobular liver necrosis or liver fibrosis, respectively). Lipid peroxidation was assessed in isolated microsomes and mitochondria with three parameters: malondialdehyde equivalents as determined by thiobarbituric acid assay, conjugated diene formation and 4-hydroxynonenal as a 2,4-dinitrophenylhydrazone derivative. To assess antioxidant systems, hepatic concentrations of glutathione, methionine and alpha-tocopherol were determined. The concentration of nonheme iron, a known prooxidant, was also measured. At wk 5, centrilobular liver necrosis was already evident in the ethanol-fed animals, with two- or threefold increases in plasma AST and ALT levels. At this stage, neither malondialdehyde equivalents nor conjugated diene values were elevated, and the 4-hydroxynonemal level was below 0.2 nmol/mg protein. Hepatic concentrations of methionine and alpha-tocopherol in these animals were increased two- and threefold, respectively, whereas the reduced glutathione level remained unchanged. When alcoholic liver disease had progressed to perivenular or bridging fibrosis at wk 16, all three parameters of lipid peroxidation showed consistent increases that were accompanied by significant reductions in the hepatic glutathione and methionine levels. Interestingly, the control animals pair-fed with the high-fat diet also had significantly elevated 4-hydroxynonenal levels at wk 16 compared to the wk 5 level.(ABSTRACT TRUNCATED AT 250 WORDS)
Discriminant function and polynomial regression methods were used to define a mental age function from scale score profile patterns found in the WAIS manual. Values on the mental age function then were calculated from WAIS scale score profiles for 164 alcoholics in the age range 35 to 74. Validity of the mental age function was evident in clear discrimination between chronological age groups in the alcoholic sample. As compared with WAIS normative values for the mental age function, the mean mental age for patients in the alcoholic sample was advanced approximately 7 years over age-matched normals. Unweighted means ANOVA revealed the accelerated mental aging of alcoholic patients to be statistically significant. This finding is discussed in the context of other research that supports a premature aging hypothesis.
The effects of chronic intake of dietary alcohol on myocardial peroxidation (measured as formation of diene conjugates), reduced glutathione content, and morphology and the protective actions of different antioxidant compounds (vitamin E and (+)-cyanidanol-3) were studied in rats. Alcohol, comprising more than 30% of the dietary calorie content, was administered to rats for six weeks. Compared with the controls, the left ventricle of the alcoholic animals had an increased diene conjugate content (5.4(0.5) vs 4.3(0.6) optical density·g wet weight⁻¹) and a slightly, but not significantly, decreased glutathione content (1.62(0.05) vs 1.66(0.07) μmol·g wet weight⁻¹). Simultaneous administration of antioxidants (vitamin E or (+)-cyanidanol-3) prevented the pathological changes in diene conjugates and significantly increased the glutathione content compared with the alcoholic rats. Electron microscopy showed remarkably few ultrastructural abnormalities in the myocardium of alcoholic animals fixed by vascular perfusion.
The data are consistent with the hypothesis that reactive oxygen radicals are involved in the ethanol induced biochemical changes and that the antioxidants could prevent the increased formation of peroxides in the myocardium.
Blood alcohol levels (BAL) were maintained at high levels (overall mean +/- S.D. achieved in 14 alcoholic rats was 216.0 +/- 120.1 mg%) in male Wistar rats for 15 to 85 days by continuous intragastric infusion of ethanol and nutritionally defined low fat liquid diet. The ethanol intake was progressively increased from 32% of total calories up to 41.4% in order to maintain high BAL. Pair-fed animals received isocaloric glucose solution and the liquid diet. Despite the low level of dietary fat (4.9% of total calories), histopathological evaluation of the liver revealed severe and progressive fatty infiltration in the alcoholic rats. In addition, following 30 days of intoxication, one third of the animals showed focal necrosis with mononuclear cell infiltration in centrilobular areas of the livers. This was correlated with the markedly elevated levels of SGOT and SGPT in these animals. Pair-fed controls showed no abnormality in the morphology of liver or blood chemistry. Chemical quantitation of liver triglycerides confirmed the histological observation, with triglyceride levels of 61.51 +/- 16.45 and 89.61 +/- 5.94 mg per gm at 30 and 85 days, respectively. Most importantly, the degree of steatosis was tightly and significantly correlated with the mean BAL achieved (r = 0.80, p less than 0.001). These data represent the first confirmation of the hypothesis that continuously high BAL correlate with the severity of alcohol-induced liver pathology.
An improved methodology is described for long-term venous and gastric cannulation in the rat. The long-term efficacy of the cannulas for blood sampling and intragastric infusion of liquid diet was determined in 18 rats. No animals died after surgery, and weight gain was normal. During the first 6 wk, blood could be drawn repetitively in 94% of the rats, and continuous intragastric infusion of diet was maintained in all the animals. For an extended period of 11 wk, success rates for blood sampling and dietary infusion were 75 and 100%, respectively. Standard hematological, histopathological, and clinical laboratory tests showed no abnormal changes. Furthermore, plasma corticosterone levels were consistently low (0.5 +/- 0.11 to 1.52 +/- 0.55 micrograms/dl) from the third postoperative day throughout a period of 6 wk, indicating that animals were under minimal stress.
A battery of cognitive tests was administered to groups of younger (34--49) and older (50--59) alcoholics and nonalcoholic control subjects. Regardless of age, alcoholics were found to be impaired on essentially all measures of learning and memory. The relevance of these findings to the premature-aging hypothesis is discussed.
Following the pioneer report of Di Luzio (Physiologist 6, 169-173, 1963) concerning the prevention of the acute ethanol-induced fatty liver by antioxidants, many observations have shown that ethanol-induced liver injury may be linked, at least partly, to an oxidative stress resulting from increased free radical production and/or decreased antioxidant defence. The disturbances induced in the major hepatic enzymatic and non-enzymatic antioxidant systems following experimental acute and chronic ethanol administration are reviewed, emphasizing the important role of dietary alpha-tocopherol in modifying the induction of oxidative stress and its usual expression as increased lipid peroxidation. Adaptative increases in some elements of the hepatic antioxidant defence partly counteract the enhanced generation of prooxidant free radicals following chronic ethanol intake. By contrast, lipid peroxidation is favoured when ethanol is administered together with a fat-rich diet and/or various xenobiotics. Chronic ethanol feeding has also been reported to potentiate the oxidative stress resulting from an acute ethanol load. By generating potent chemoattractants for human neutrophils and/or by stimulating the expression of genes involved in collagen biosynthesis, liver lipid peroxidation may play an important role in the progression of steatosis to hepatitis and cirrhosis. Oxidative stress has been shown not to be restricted to the liver, but also to affect, under some experimental conditions of ethanol administration, extrahepatic tissues, such as the central nervous system, the heart and the testes. This stress can be partly prevented by vitamin E supplementation. Ethanol-induced antioxidant disturbances have also been reported in clinical studies in blood and liver biopsies. Pharmacological antioxidants could have beneficial effects in reducing the incidence of ethanol-induced changes in cellular lipids, proteins and nucleic acids. The antioxidants considered could act by reducing free radical production (e.g. chelators of redox-active iron derivatives), trapping free radicals themselves, interrupting the peroxidation process or reinforcing the natural antioxidant defence.
We evaluated the role of changes in cytochrome P-450 2E1 (CYP 2E1) and lipid peroxidation in relation to development of severe liver injury in fish oil-ethanol-fed rats. The experimental animals (male Wistar rats) were divided into 5 rats/group and were fed the following diets for 1 month: corn oil and ethanol (CO+E) or corn oil and dextrose (CO+D), and fish oil and ethanol (FO+E) or fish oil and dextrose (FO+D). For each animal, microsomal analysis of CYP 2E1 protein, aniline hydroxylase activity, fatty acid composition, and conjugated dienes was conducted. Also, evaluation of severity of pathology was done for each rat. The mean +/- SD of the pathology score was significantly higher (p < 0.01) in the FO+E (6.0 +/- 1.3) group than in the CO+E group (3.0 +/- 0.5). No pathological changes were evident in the dextrose-fed controls. The CYP 2E1 protein levels (mean +/- SD) were significantly higher (p < 0.01) in the FO+E group (13.1 +/- 2.0) compared with the CO+E (4.7 +/- 1.2) and FO+D (1.8 +/- 0.5) groups. Higher levels of eicosapentaenoic and docosahexaenoic acids and lower levels of arachidonic acid were detected in liver microsomes from rats fed fish oil compared with corn oil. A significant correlation was obtained between CYP 2E1 protein and conjugated diene levels (r = 0.78, p < 0.01). Our results showing markedly increased CYP 2E1 induction and lipid peroxidation in the FO+E group provides one possible explanation for the greater severity of liver injury in this group.
We used the intragastric feeding rat model for alcoholic liver disease to investigate the relationship between pathological severity and lipid peroxidation. Lipid peroxidation was assessed by measurement, in plasma, of a novel noncyclooxygenase-derived prostanoid (8-isoprostane). Six groups of animals fed ethanol and different dietary fats (saturated fat, corn oil and fish oil) were sacrificed at 1 month. Histological liver examination, plasma measurements of 8-isoprostane and measurements of microsomal conjugated dienes were carried out. Animals fed fish oil and ethanol developed the most severe liver injury and had the highest 8-isoprostane levels in plasma (919 +/- 112 pg/ml). These levels were significantly higher than the levels seen in the corn oil-ethanol (498 +/- 105 pg/ml) (P < 0.02) and saturated fat-ethanol (28.6 +/- 11.8 pg/ml) (P < .001) groups. Rats fed saturated fat and dextrose and corn oil and dextrose had levels of < 20 pg/ml. However rats fed fish oil and dextrose had, on average, 8-isoprostane levels about 100-fold higher than those seen in the saturated fat-dextrose and corn oil-dextrose groups. A significant correlation between pathological severity and plasma 8-isoprostane levels was seen in the fish oil (r = 0.92, P < .001) and non-fish oil-treated groups (r = 0.94, P < .001). A significant correlation also was seen between 8-isoprostane levels and liver microsomal conjugated dienes (r = 0.93, P < .001). Our results provide strong support for the hypothesis that lipid peroxidation in ethanol-fed rats contributes to pathological liver injury.
Metabolism, like other aspects of life, involves tradeoffs. Oxidant by-products of normal metabolism cause extensive damage to DNA, protein, and lipid. We argue that this damage (the same as that produced by radiation) is a major contributor to aging and to degenerative diseases of aging such as cancer, cardiovascular disease, immune-system decline, brain dysfunction, and cataracts. Antioxidant defenses against this damage include ascorbate, tocopherol, and carotenoids. Dietary fruits and vegetables are the principal source of ascorbate and carotenoids and are one source of tocopherol. Low dietary intake of fruits and vegetables doubles the risk of most types of cancer as compared to high intake and also markedly increases the risk of heart disease and cataracts. Since only 9% of Americans eat the recommended five servings of fruits and vegetables per day, the opportunity for improving health by improving diet is great.
We have previously shown that the treatment with diallyl sulfide (DAS) and phenylethyl isothiocyanate (PIC) of rats receiving ethanol in the alcohol tube-feeding model effectively suppressed the induction of cytochrome P4502E1 (CYP2E1) by ethanol. Here we report that rat treatment with DAS and PIC significantly decreased the trapping of hydroxyethyl free radicals in liver microsomes incubated in vitro with ethanol. Furthermore, these inhibitors also greatly reduced the production of hydroxyethyl radical-derived epitopes detectable in vivo in the liver of ethanol-fed rats. The action of DAS and PIC on the formation of hydroxyethyl radicals paralleled their inhibitory effect on lipid peroxidation as monitored using, respectively, liver malonildialdehyde (MDA) and plasma lipid hydroperoxide levels as well as by the titers of antibodies versus MDA adducts to proteins. Thus, these results indicated a link between the induction of CYP2E1 by ethanol, the formation of hydroxyethyl radicals and the stimulation of lipid peroxidation. The pathological scores in the livers of rats fed with ethanol plus or minus DAS and PIC also correlated with levels of hydroxyethyl radical-derived epitopes. Rats fed intragastrically with ethanol developed antibodies and the formation of these antibodies was greatly reduced by DAS and PIC. Taken together these results suggest that CYP2E1 plays an important role in the generation of hydroxyethyl radicals during chronic alcohol feeding and that ethanol-derived free radicals might play a role in the onset of liver injury in this model of alcohol administration.
Previous studies in our laboratory have demonstrated the effect of Schisandrin B (Sch B),an active ingredient of the fruit of Schisandra chinensis, on enhancing the hepatic glutathione antioxidant system in mice, as evidenced by the hepatoprotection against carbon tetrachloride (CCl4) toxicity. In the present study, the mechanism involved in the hepatoprotection afforded by Sch B treatment was investigated. Treating female Balb/c mice with 1, 3-bis(2-chloroethyl)-1-nitrosourea, an inhibitor of glutathione reductase (GRD), at a dose of 2 mmol/kg (i.p.) did not abrogate the hepatoprotective action of Sch B in CCl4-treated mice. The result indicates that the increased activity of hepatic GRD is not ascribable to the hepatoprotective action of Sch B. In control mice, the same Sch B treatment regimen caused an enhancement in hepatic mitochondrial glutathione redox status, as indicated by the significant increase and decrease in reduced and oxidized glutathione levels, respectively. While the CCl4 intoxication greatly impaired mitochondrial glutathione redox status, the beneficial effect of Sch B treatment became more evident after CCl4 challenge. Our results strongly suggest that the mechanism of hepatoprotection afforded by Sch B treatment may involve the enhancement of mitochondrial glutathione redox status.
Liver lipid peroxidation, nonheme iron, antioxidants, and protein oxidation were investigated in experimental alcohol-induced liver disease in the rat. Wistar male rats were intragastrically and continuously infused for 4 weeks with a high-fat diet plus an ethanol or an isocaloric amount of dextrose, maintaining a high blood alcohol level (200-300 mg%). This model induced fatty liver, spotty necrosis, and focal inflammation. This pathology was associated with an enhanced lipid peroxidation and a decrease in the major antioxidant factors. Hepatic alpha-tocopherol and glutathione concentrations were significantly decreased in ethanol-fed rats. Glutathione peroxidase (GPx) was also decreased, whereas glutathione S-transferase (GST) was unaffected. The nonheme iron level was significantly decreased. Protein oxidation was assessed through three parameters: protein thiols, protein carbonyl groups, and the activity of glutamine synthetase (GS), a centrilobular enzyme particularly susceptible to free-radical-mediated damage. Ethanol-fed rats had decreased protein thiol concentrations and reduced GS activity, together with increased protein carbonyls. A significant correlation between GS activity and the pathological score was observed. This study confirms the ethanol-related increase in lipid peroxidation and shows that ethanol impairs the hepatic antioxidant potential. Furthermore, evidence of oxidative protein damage is given, including decreased activity of a key enzyme of ammonia metabolism. These protein disturbances may contribute to the pathogenesis of the observed liver damage.
As a preliminary approach to exploring whether the methylenedioxy group of the dibenzocyclooctadiene skeleton of schisandrins plays an important role in hepatic mitochondrial-reduced glutathione (GSH) stimulatory activity, we examined the effects of three schisandrins, namely schisandrin A (Sch A), schisandrin B (Sch B), and schisandrin C (Sch C), on carbon tetrachloride (CCl4) hepatotoxicity and hepatic mitochondrial GSH status in mice. Pretreating mice with Sch A at a daily oral dose of 1 mmol/kg for 3 days did not protect against CCl4 hepatotoxicity, whereas pretreatment with Sch B or Sch C at the same dosage regimen produced almost complete protection. The hepatoprotection afforded by Sch B or Sch C pretreatment was associated with significant increases in the hepatic mitochondrial GSH level and glutathione reductase (EC 1.6.4.2) activity. Our results indicate that the methylenedioxy group of the dibenzocyclooctadiene skeleton of schisandrin is an important structural determinant in the stimulation of hepatic mitochondrial GSH, particularly under conditions of CCl4 intoxication.
Tumor necrosis factor (TNF)α, a pivotal cytokine involved in inflammation, is produced primarily by Kupffer cells in the liver. It has been shown that inactivation of Kupffer cells prevents alcohol-induced liver injury; therefore, the purpose of this study was to determine if neutralizing anti-TNF-α antibody is also effective. Male Wistar rats were exposed to ethanol (11 to 12 g · kg-1 · d-1) continuously for up to 4 weeks via intragastric feeding using an enteral feeding model. Before ethanol exposure, polyclonal anti-mouse TNF-α rabbit serum was injected (2.0 mg/kg intravenously). There were no significant differences in body weight, mean ethanol concentration, or cyclic patterns of ethanol in urine when ethanol-and ethanol plus antibody-treated groups were compared. Expression of TNF- α and macrophage inflammatory protein 2 (MIP-2) messenger RNA (mRNA), determined using reverse transcription-polymerase chain reaction, was three- to four-fold higher in livers of ethanol-treated rats than in those of rats fed an ethanol-free, high-fat control diet. In addition, MIP-2 levels were also elevated when detected by Northern blot analysis. Anti-TNF-α antibody did not affect expression of mRNA for interleukin (IL) 1α, IL-6, transforming growth factor β1, or TNF-α. However, MIP-2 mRNA expression, which is regulated by TNF-α, was decreased significantly by anti-TNF-α antibody treatment. Serum aspartate transaminase levels were elevated in ethanol-treated rats to 136 ± 12 IU/L after 4 weeks but only reached 90 ± 5 IU/L (P < .05) in rats treated with anti-TNF-α antibody. The hepatic inflammation and necrosis observed in ethanol-fed rats were attenuated significantly by antibody treatment, and steatosis was not. These results support the hypothesis that TNF-α plays an important role in inflammation and necrosis in alcohol-induced liver injury and that treatment with anti-TNF-α antibody may be therapeutically useful in this disease.
Increased hepatic oxidative stress with ethanol administration is hypothesized to be caused either by enhanced pro-oxidant production or decreased levels of antioxidants or both. We used the intragastric feeding rat model to assess the relationship between hepatic antioxidant enzymes and pathological liver injury in animals fed different dietary fats. Male Wistar rats (5 per group) were fed ethanol with either medium-chain triglycerides (MCTE), palm oil (PE), corn oil (CE), or fish oil (FE). Control animals were fed isocaloric amounts of dextrose instead of ethanol with the same diets. The following were evaluated in each group: liver pathology, lipid peroxidation, manganese superoxide dismutase (MnSOD) levels, copper-zinc SOD (CuZnSOD) levels, glutathione peroxidase (GPX) levels, and catalase (CAT) levels. All enzymes were evaluated using activity assays and immunoblots. Rats fed FE showed the most severe pathology (fatty liver, necrosis, and inflammation), those fed CE showed moderate changes, those fed PE showed fatty liver only, and those fed MCTE were normal. Parameters indicative of lipid peroxidation (conjugated dienes and thiobarbituric acid-reactive substances) were also greater in rat livers from animals fed the diets high in polyunsaturated fatty acids (CE and FE). CuZnSOD, GPX, and CAT activities showed an inverse correlation (r=-.92, P < .01) with severity of pathological injury, with the lowest levels for both enzymes found in FE-fed rats. Decreased enzyme activity in CE- and FE-fed rats was accompanied by similar decreases in immunoreactive protein. Ethanol administration did not cause significant decreases in enzyme activity in groups that showed no necroinflammatory changes (MCTE and PE). MnSOD activity showed no significant change in any ethanol-fed group. Our results show that decreases in CuZnSOD, GPX, and CAT occur in rats showing pathological liver injury and also having the highest levels of lipid peroxidation. These results suggest that feeding dietary substrates that enhance lipid peroxidation can exacerbate both ethanol-induced oxidative damage as well as necroinflammatory changes. The decrease in activity of antioxidant enzymes observed in animals fed diets high in polyunsaturated fatty acids and ethanol could possibly increase the susceptibility to oxidative damage and further contribute to ethanol-induced liver injury.
The purpose of this investigation was to assess the effect of chlormethiazole treatment on liver damage in the experimental rat intragastric ethanol-feeding model of alcoholic liver disease. Chlormethiazole has been used in the treatment of alcoholic withdrawal and has been shown to inhibit cytochrome P4502E1. Since treatment of experimental alcoholic liver disease with CYP2E1 inhibitors had an ameliorating effect on liver injury in the rat, chlormethiazole was used to see if it had a similar effect. Rats fed ethanol for 2 months had significantly less liver injury when chlormethiazole was added to the diet, fed intragastrically. The CYP2E1 apoprotein levels, which were increased by ethanol feeding, were also increased when chlormethiazole was fed with ethanol. Chlormethiazole inhibited the increase in the ethanol-induced CYP2E1 activity in vivo, as measured by chlorzoxazone 6-hydroxylation, but did not affect the level of CYP2E1 apoprotein. Likewise, the reduction in proteasome proteolytic enzyme activity produced by ethanol feeding was blunted in chlormethiazole-fed rats. These results support the conclusion that chlormethiazole treatment partially protects the liver from injury by inhibiting CYP2E1 activity in vivo.
Mitochondria are intimately involved in the generation of and defense against reactive oxygen species (ROS). Mitochondria are themselves targets of oxidative stress and also contribute to mechanisms by which oxidative stress-related signals control cell fate. Ethanol promotes oxidative stress, both by increasing ROS formation and by decreasing cellular defense mechanisms. These effects of ethanol are prominent in the liver, the major site of ethanol metabolism in the body. The question remains to what extent this contributes to ethanol-dependent tissue damage or the susceptibility of cells to other stressors. In this review, we consider how mitochondrial actions of ethanol influence oxidative stress management of liver cells. Mitochondrial electron transport constitutes the major intracellular source of ROS, and ethanol treatment imposes conditions that promote ROS formation by mitochondria, the effects of which may be enhanced by a decrease in mitochondrial oxidative stress defenses. A significant target of ethanol-related increases in oxidative stress is mitochondrial DNA. Ethanol-induced damage to mitochondrial DNA, if not adequately repaired, impairs mitochondrial function, which further increases oxidative stress in the cell, leading to a vicious cycle of accumulating cell damage that is more apparent with advancing age. Uncontrolled mitochondrial formation of ROS promotes the inappropriate activation of the mitochondrial permeability transition, increasing the sensitivity of cells to other pro-apoptotic or damage signals. In combination with ethanol-induced defects in mitochondrial function, these alterations may promote both apoptotic and necrotic cell death in response to otherwise benign or beneficial challenges and contribute to the onset or progression of alcohol-induced liver diseases.
The in vivo antioxidant action of a lignan-enriched extract of the fruit of Schisandra chinensis (FS) and an anthraquinone-containing extract of the root of Polygonum multiflorum (PME) was compared with their respective active constituents schisandrin B (Sch B) and emodin by examining their effect on hepatic mitochondrial glutathione antioxidant status in control and carbon tetrachloride (CCl4)-intoxicated mice. FS and PME pretreatments produced a dose-dependent protection against CCl4 hepatotoxicity, with the effect of FS being more potent. Pretreatment with Sch B, emodin or α-tocopherol (α-Toc) also protected against CCl4 hepatotoxicity, with the effect of Sch B being more potent. The extent of hepatoprotection afforded by FS/Sch B and PME/emodin pretreatment against CCl4 toxicity was found to correlate well with the degree of enhancement in hepatic mitochondrial glutathione antioxidant status, as evidenced by increases in reduced glutathione level and activities of glutathione reductase, glutathione peroxidase as well as glutathione S-transferases, in both control and CCl4-intoxicated mice. α-Toc, which did not enhance mitochondrial glutathione antioxidant status, seemed to be less potent in protecting against CCl4 hepatotoxicity. The ensemble of results indicates that FS/PME produced a more potent in vivo antioxidant action than α-Toc by virtue of their ability to enhance hepatic mitochondrial glutathione antioxidant status and that the differential potency of FS and PME can be attributed to the difference in in vivo antioxidant potential between Sch B and emodin.
Abbreviations
ALT:alanine aminotransferases
CCl4:carbon tetrachloride
FS:lignan-enriched extract of Schisandra fruit
GRD:glutathione reductase
GSH:reduced glutathione
GSH-Px:Se-glutathione peroxidase
GST:glutathione S-transferases
mt:mitochondrial
MDA:malondialdehyde
PME:anthraquinone-containing fraction of Polygonum root
Sch B:schisandrin B
SDH:sorbitol dehydrogenase
α-Toc:α-tocopherol
Correlations between cerebrospinal fluid (CSF) concentrations of monoamine metabolites (MAM) and brain structure have been described in schizophrenia, but not in alcoholism. To investigate the relationship between monoaminergic transmission and brain structure in alcoholism, the metabolites of dopamine (homovanillic acid, HVA), norepinephrenine (3-methoxy-4-hydroxyphenylethyleneglycol, MHPG) and serotonin (5-hydroxyindoleacetic acid, 5-HIAA) were measured in lumbar CSF in 54 alcohol-dependent patients and 20 healthy subjects. The volumes of the cerebrum, total grey and white matter, total and ventricular CSF, left and right hippocampus, and corpus callosum area were measured with MRI. MHPG and age were positively correlated in alcoholic women. The MAM concentrations were not significantly correlated with the MRI volumes in the subject categories. There were no differences in MAM across subjects defined by diagnosis and gender, age of onset of alcoholism or comorbidity of psychiatric disorders. Total CSF, cerebrum, and white and grey matter tissue volumes differed between patients and healthy subjects. The greatest difference was the white matter reduction in alcoholic women. In alcoholic women and men, monoaminergic neurotransmission measured by the CSF MAM HVA, MHPG, and 5-HIAA is not significantly correlated with the size of different brain structures.
Ethanol-induced oxidative stress appears to play a major role in mechanisms by which ethanol causes liver injury. Many pathways have been suggested to contribute to the ability of ethanol to induce a state of oxidative stress. One central pathway appears to be the induction of the CYP2E1 form of cytochrome P450 enzymes by ethanol. CYP2E1 is of interest because of its ability to metabolize and activate many toxicological substrates, including ethanol, to more reactive, toxic products. Levels of CYP2E1 are elevated under a variety of physiological and pathophysiological conditions, and after acute and chronic alcohol treatment. CYP2E1 is also an effective generator of reactive oxygen species such as the superoxide anion radical and hydrogen peroxide, and in the presence of iron catalysts, produces powerful oxidants such as the hydroxyl radical. This Review Article summarizes some of the biochemical and toxicological properties of CYP2E1, and briefly describes the use of HepG2 cell lines developed to constitutively express the human CYP2E1 in assessing the actions of CYP2E1. Regulation of CYP2E1 is quite complex and will be briefly reviewed. Possible therapeutic implications for treatment of alcoholic liver injury by inhibition of CYP2E1 or CYP2E1-dependent oxidative stress will be discussed, followed by some future directions which may help to understand the actions of CYP2E1 and its role in alcoholic liver injury.
We carried out this experiment to evaluate the relationship between isoforms of cytochrome P450 (P450) and liver injury in lipopolysaccharide (LPS)-induced endotoxemic rats. Male rats were intraperitoneally administered phenobarbital (PB), a P450 inducer, for 3 days, and 1 day later, they were intravenously given LPS. PB significantly increased P450 levels (200% of control levels) and the activities (300-400% of control) of the specific isoforms (CYP), CYP3A2 and CYP2B1, in male rats. Plasma AST and ALT increased slightly more in PB-treated rats than in PB-nontreated (control) rats with LPS treatment. Furthermore, either troleandomycin or ketoconazole, specific CYP3A inhibitors, significantly inhibited LPS-induced liver injury in control and PB-treated male rats. To evaluate the oxidative stress in LPS-treated rats, in situ superoxide radical detection using dihydroethidium (DHE), hydroxy-2-nonenal (HNE)-modified proteins in liver microsomes and 8-hydroxydeoxyguanosine (8-OHdG) in liver nuclei were measured in control and PB-treated rats. DHE signal intensity, levels of HNE-modified proteins, and 8-OHdG increased significantly in PB-treated rats. LPS further increased DHE intensity, HNE-modified proteins, and 8-OHdG levels in normal and PB-treated groups. CYP3A inhibitors also inhibited the increases in these items. Our results indicate that the induction or preservation of CYP isoforms further promotes LPS-induced liver injury through mechanisms related to oxidative stress. In particular, CYP3A2 of P450 isoforms made an important contribution to this LPS-induced liver injury.
Synthesized in the cytosol of cells, a fraction of cytosolic glutathione (GSH) is then transported into the mitochondrial matrix where it reaches a high concentration and plays a critical role in defending mitochondria against oxidants and electrophiles. Evidence mainly from kidney and liver mitochondria indicated that the dicarboxylate and the 2-oxoglutarate carriers contribute to the transport of GSH across the mitochondrial inner membrane. However, differential features between kidney and liver mitochondrial GSH (mGSH) transport seem to suggest the existence of additional carriers the identity of which remains to be established. One of the characteristic features of the hepatic mitochondrial transport of GSH is its regulation by membrane fluidity. Conditions leading to increased cholesterol deposition in the mitochondrial inner membrane such as in alcohol-induced liver injury decrease membrane fluidity and impair the mitochondrial transport of GSH. Depletion of mitochondrial GSH by alcohol is believed to contribute to the sensitization of the liver to alcohol-induced injury through tumor necrosis factor (TNF)-mediated hepatocellular death. Through control of mitochondrial electron transport chain-generated oxidants, mitochondrial GSH modulates cell death and hence its regulation may be a key target to influence disease progression and drug-induced cell death.
In the course of searching for hepatoprotective agents from natural products, six compounds were isolated from the MeOH extract of the leaves of Juglans sinensis, as guided by their DPPH free radical scavenging activity. The structures were determined as juglanoside B (1), quercetin 3-O-alpha-L-arabinofuranoside (avicularin, 2), quercetin 3-O-alpha-L-arabinopyranoside (guaijaverin, 3), quercetin 3-O-alpha-L-rhamnopyranoside (quercitrin, 4), (+)-catechin (5) and quercetin 3-O-beta-D-galactopyranoside (hyperin, 6). Compounds 2-6 showed significant DPPH free radical scavenging effects. An evaluation for the hepatoprotective activity of the isolated compounds on drug-induced cytotoxicity was conducted, and compounds 1, 2, and 5 showed protective effects against nitrofurantoin-induced cytotoxicity, and compound 5 also exhibited a moderate protective effect on amiodarone-induced cytotoxicity in Hep G2 cells.
Alcohol-induced lung damage may be associated with increased oxidative stress.
Our aim was to investigate alcohol-induced changes in the biochemistry and histopathology of the lung.
Rats were divided into two groups, a control group and an ethanol group. The ethanol group received 2 g/kg ethanol (total: 3 ml) intraperitoneally. The controls were given the same amount of saline via the same route. Three hours later, the rats were sacrificed, and blood and lung tissue samples were obtained. Oxidative stress was assessed by measuring the levels of erythrocyte reduced glutathione (GSH), tissue malondialdehyde (MDA), myeloperoxidase (MPO) and Na(+)-K(+) ATPase. Histopathologic evaluation of the lung tissues was also performed.
In the ethanol group, serum and tissue MDA levels and MPO activities were increased (p = 0.007, p = 0.001 and p = 0.000), and lung tissue Na(+)-K(+) ATPase activities and erythrocyte GSH were decreased (p = 0.001 and p = 0.000) compared to the controls. Histopathologic examination demonstrated alveolocapillary thickening, alveolar degeneration, leukocyte infiltration and erythrocyte extravasation in the lungs of the ethanol group (p < 0.05).
These results suggest that high-dose acute alcohol administration aggravates systemic and local oxidative stress leading to acute lung injury, ranging from mild pulmonary dysfunction to severe lung injury. It should be borne in mind that rapid onset of the acute respiratory distress syndrome (ARDS) may also be due to increased oxidative stress following alcohol abuse, especially when ischemic disturbances, e.g. coronary heart disease, acute ischemia of the extremities and traumatic accidents, are concomitantly present. Therefore, precautions against ARDS may prevent morbidity and mortality in alcohol-induced lung damage in at-risk patients.
Chronic exposure to high doses of alcohol results in many pathophysiologic changes in cellular function caused by the alcohol itself and the effects of its metabolism (ie, generation of acetaldehyde, nicotinamide adenine dinucleotide [NADH], free radicals, and oxidative stress). However, the role of each of these effects on the testis, ovary, kidney, and lung in chronic alcoholism must be investigated. It is hypothesized that cysteine-methionine and vitamin C might neutralize harmful compounds and potentiate the antioxidant capacity of the cell or tissue. In this study, rats were fed regular diets and were maintained in the following groups for 90 days: control group; alcoholic group (2.5 g of 50% ethanol/kg body wt administered intragastrically every other day); and alcoholic with antioxidant supplement group (2.5 g of 50% ethanol plus a solution containing 200 mg vitamin C, 100 mg cysteine, and 100 mg methionine/kg body wt administered intragastrically every other day). After treatment had been completed, rat blood, testis, ovary, kidney, and lung were taken for biochemical analysis. Mean alcohol level in the alcoholic group was raised (by 40%) compared with that in the control group, but it was lower (by 30%) in the antioxidant-supplemented group than in the alcoholic group. In accordance with the levels of alcohol, oxidized protein and lipid content in the testis, ovary, kidney, and lung were low in the control group, higher in the antioxidant-supplemented group, and highest in the alcoholic group. It is interesting to note that levels of glutathione in the testis and lung of the alcoholic group were lower than those in both the control and antioxidant-supplemented groups. In conclusion, chronic alcohol administration led to a significant increase in the level of protein oxidation in the ovary and kidney of rats. Simultaneous intake of ascorbate/L-cys/L-met, along with ethanol, partly attenuated the amount of lipid and protein oxidation that occurred in tissues with oxidative stress caused by alcohol consumption.