Impact of massive ascorbic acid supplementation on alcohol induced oxidative stress in guinea pigs

Potential inhibitory effects of low-dose thoron inhalation and ascorbic acid administration on alcohol-induced hepatopathy in mice

Although thoron inhalation exerts antioxidative effects in several organs, there are no reports on whether it inhibits oxidative stress-induced damage. In this study, we examined the combined effects of thoron inhalation and ascorbic acid (AA) administration on alcohol-induced liver damage. Mice were subjected to thoron inhalation at 500 or 2000 Bq/m3 and were administered 50% ethanol (alcohol) and 300 mg/kg AA. Results showed that although alcohol administration increased the levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) in the serum, the combination of thoron inhalation (500 Bq/m3) and AA administration 24 h after alcohol administration effectively inhibited alcohol-induced liver damage. The combination of thoron inhalation (500 Bq/m3) and AA administration 24 h after alcohol administration increased catalase (CAT) activity. Alcohol administration significantly decreased glutathione (GSH) levels in the liver. The GSH content in the liver after 2000 Bq/m3 thoron inhalation was lower than that after 500 Bq/m3 thoron inhalation. These findings suggest that the combination of thoron inhalation at 500 Bq/m3 and AA administration has positive effects on the recovery from alcohol-induced liver damage. The results also suggested that thoron inhalation at 500 Bq/m3 was more effective than that at 2000 Bq/m3, possibly because of the decrease in GSH content in the liver. In conclusion, the combination of thoron inhalation at 500 Bq/m3 and AA administration promoted an early recovery from alcohol-induced liver damage.

Vitamin Supplements as a Nutritional Strategy against Chronic Alcohol Consumption? An Updated Review

Several studies have shown that blood vitamin levels are low in alcoholic patients. In effect, alcohol use abuse is considered a chronic disease that promotes the pathogenesis of many fatal diseases, such as cancer and liver cirrhosis. The alcohol effects in the liver can be prevented by antioxidant mechanisms, which induces enzymatic as well as other nonenzymatic pathways. The effectiveness of several antioxidants has been evaluated. However, these studies have been accompanied by uncertainty as mixed results were reported. Thus, the aim of the present review article was to examine the current knowledge on vitamin deficiency and its role in chronic liver disease. Our review found that deficiencies in nutritional vitamins could develop rapidly during chronic liver disease due to diminished hepatic storage and that inadequate vitamins intake and alcohol consumption may interact to deplete vitamin levels. Numerous studies have described that vitamin supplementation could reduce hepatotoxicity. However, further studies with reference to the changes in vitamin status and the nutritional management of chronic liver disease are in demand.

Multigenerational selection towards longevity changes the protective role of vitamin C against graphene oxide-induced oxidative stress in house crickets

This research was designed to investigate changes that can arise in an invertebrate organism due to stress caused by a strong prooxidant, graphene oxide (GO), and a potent antioxidant, vitamin C. The study aimed to investigate if vitamin C may support convalescence after chronic GO intoxication. We investigated the toxicity of chronic dietary graphene oxide administration in house cricket (Acheta domesticus) types: wild and selected for longevity (with a better developed antioxidant system, conducive to long life). Vitamin C was applied immediately after cessation of graphene oxide intoxication to check if it can support the remedial effect. The condition of cells, DNA stability, catalase activity, and the reproduction potential, measured as the Vitellogenin (Vg) protein expression level, were investigated in control and GO treated groups, recovery groups (-GO), and recovery groups with Vit. C (-GO + Vit.C). In this study vitamin C had no evident remedial effect on the house crickets exposed to graphene oxide. Most probably, the mechanism of vitamin C action, in case of intoxication with nanoparticles, is much more complicated. In the context of the results obtained, it is worth considering whether Vit. C, applied after GO intoxication, causes further disturbance of homeostasis in terms of the cells' redox potential.

Liver Histological Improvement After Administration of High-Dose Vitamin C in Guinea Pig with Nonalcoholic Steatohepatitis

Background: Vitamin C is a strong antioxidant, and the health effects of vitamin C megadoses have not been validated despite the apparent health benefits. Therefore, the present study sought to confirm the effects of vitamin C megadoses. Materials and Methods : Four groups of six guinea pigs were used. Each group was fed one of the following diets for three weeks: normal diet, methionine choline-deficient diet, methionine choline-deficient diet + vitamin C megadose (MCD + vit C 2.5 g/kg/day), and methionine-choline deficient diet + ursodeoxycholic acid (MCD + UDCA 30 mg/kg/day). The MCD diet was given to induce nonalcoholic steatohepatitis, and UDCA was used to treat nonalcoholic steatohepatitis. Three weeks after initial diet administration, the results of biochemical tests and liver biopsy were compared between the groups. Results: The cytoplasm state was similar in the MCD + vit C and MCD + UDCA groups, exhibiting clearing of the cytoplasm and ballooning degeneration. However, macrovesicular steatosis was not observed in the MCD + vit C group. Aspartate transaminase and alanine transaminase were elevated significantly following vitamin C administration. Conclusions: The present study confirmed that alone vitamin C megadoses are potential remedies for nonalcoholic steatohepatitis, based on the liver biopsy results of guinea pigs that were unable to synthesize vitamin C.

Postnatal nutritional treatment of neurocognitive deficits in fetal alcohol spectrum disorder

Ethanol is the most important teratogen agent in humans. Prenatal alcohol exposure can lead to a wide range of adverse effects, which are broadly termed as fetal alcohol spectrum disorder (FASD). The most severe consequence of maternal alcohol abuse is the development of fetal alcohol syndrome, defined by growth retardation, facial malformations, and central nervous system impairment expressed as microcephaly and neurodevelopment abnormalities. These alterations generate a broad range of cognitive abnormalities such as learning disabilities and hyperactivity and behavioural problems. Socioeconomic status, ethnicity, differences in genetic susceptibility related to ethanol metabolism, alcohol consumption patterns, obstetric problems, and environmental influences like maternal nutrition, stress, and other co-administered drugs are all factors that may influence FASD manifestations. Recently, much attention has been paid to the role of nutrition as a protective factor against alcohol teratogenicity. There are a great number of papers related to nutritional treatment of nutritional deficits due to several factors associated with maternal consumption of alcohol and with eating and social disorders in FASD children. Although research showed the clinical benefits of nutritional interventions, most of work was in animal models, in a preclinical phase, or in the prenatal period. However, a minimum number of studies refer to postnatal nutrition treatment of neurodevelopmental deficits. Nutritional supplementation in children with FASD has a dual objective: to overcome nutritional deficiencies and to reverse or improve the cognitive deleterious effects of prenatal alcohol exposure. Further research is necessary to confirm positive results, to determine optimal amounts of nutrients needed in supplementation, and to investigate the collective effects of simultaneous multiple-nutrient supplementation.

Hepatoprotective and nephroprotective effects of sardinelle (Sardinella aurita) protein hydrolysate against ethanol-induced oxidative stress in rats

Ethanol consumption-induced oxidative stress that is a major etiological factor has been proven to play important roles in organs' injury. In the present study, we investigated the protective effect of fish protein hydrolysate prepared from the heads and viscera of sardinelle (Sardinella aurita) (SPH) against the toxicity of ethanol on the liver and kidney of adult male rats. Animals were divided into four groups of six animals each: group C served as control, group Eth received 30 % ethanol solution at the dose of 3 g/kg body weight, group SPH received only 7.27 mg of SPH/kg body weight, and group Eth-SPH received ethanol and SPH simultaneously at the doses of 30 % and 7.27 mg/kg body weight, respectively. All groups were treated by gavage way for 15 days. Ethanol treatment decreased the defense enzymatic system including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), which increased after the co-administration of SPH. Malondialdehyde (MDA) and toxicity biomarker levels such as aspartate transaminase (AST) and alanine transaminase (ALT) and alcaline phosphatase (ALP) and gamma-glutamyl transaminase (GGT) activities were enhanced after chronic ethanol treatment and reduced by co-treatment with SPH. The histological examination of the liver and kidney confirmed biochemical changes in ethanol-treated rats and demonstrated the protective role of SPH.

Advances in the development of novel antioxidant therapies as an approach for fetal alcohol syndrome prevention

Ethanol is the most common human teratogen, and its consumption during pregnancy can produce a wide range of abnormalities in infants known as fetal alcohol spectrum disorder (FASD). The major characteristics of FASD can be divided into: (i) growth retardation, (ii) craniofacial abnormalities, and (iii) central nervous system (CNS) dysfunction. FASD is the most common cause of nongenetic mental retardation in Western countries. Although the underlying molecular mechanisms of ethanol neurotoxicity are not completely determined, the induction of oxidative stress is believed to be one central process linked to the development of the disease. Currently, there is no known effective strategy for prevention (other than alcohol avoidance) or treatment. In the present review we will provide the state of art in the evidence for the use of antioxidants as a potential therapeutic strategy for the treatment using whole-embryo and culture cells models of FASD. We conclude that the imbalance of the intracellular redox state contributes to the pathogenesis observed in FASD models, and we suggest that antioxidant therapy can be considered a new efficient strategy to mitigate the effects of prenatal ethanol exposure.

Effects of vitamins E and C supplementation on hepatic glutathione peroxidase activity and tissue injury associated with ethanol ingestion in malnourished rats

BACKGROUND

Oxidative stress has been associated with tissue injury in alcoholic liver disease. Although this close association is well known, whether prevention of oxidative stress retards tissue injury has not been thoroughly investigated.

OBJECTIVE

The aim of this study was to determine the effects of supplementation with vitamins E and C on antioxidant enzyme status and histologic changes in hepatic tissue in a rat model of alcoholic liver disease.

METHODS

This 8-week, blinded, controlled study was conducted at the Department of Internal Medicine, Trakya University, Edirne, Turkey. Weanling albino female protein-deficient Wistar rats weighing ∼200 g were randomly assigned to 1 of 6 groups: (1) liquid diet+ethanol+vitamin E 15 mg/kg PO (LDetvitE); (2) liquid diet+ethanol+vitamin C 10 mg/kg PO (LDetvitC); (3) liquid diet+ethanol+vitamin E 15 mg/kg+vitamin C 10 mg/kg PO (LDetvitEC); (4) liquid diet+ethanol (LDet); (5) liquid diet+isocaloric sucrose (LDS); and (6) normal diet (control). The primary end point of the study was to determine whether antioxidant vitamin E/C combination therapy prevents development of hepatic fibrosis (ie, cirrhosis in a period of 1 year). After being euthanized at week 8, the rats were weighed, and their livers and spleens were weighed. Hepatic tissue specimens were histopathologically assessed according to the Brunt system. Hepatic tissue glutathione peroxidase, superoxide dismutase, and catalase activities were determined. Biochemical tissue collagen concentrations were measured to determine the presence of hepatic fibrosis.

RESULTS

Seventy-two rats were included in the study (mean [SE] weight, 205 [21] g) (12 rats per group). Initially planned to last 48 weeks, the study was terminated at 8 weeks due to the death of 3 rats in each group (except the LDS group and control group). The relative liver weight was significantly lower in the LDetvitEC group compared with that in the LDet group (mean [SE], 3.7% [0.5%] vs 4.8% [0.9%]; P<0.01). Mean (SE) hepatic tissue glutathione peroxidase activity was significantly reduced in the LDet-treated rats compared with controls (1.2 [0.2] vs 2.6 [0.3] U/mg protein; P<0.001). The groups that received supplementation with vitamin E, vitamin C, and vitamins E and C combined had significantly more hepatic glutathione peroxidase activity (mean [SE], 2.1 [0.5], 2.5 [0.2], and 2.6 [0.7] U/mg protein, respectively) compared with the LDet group (1.2 [0.2] U/mg protein) (all, P<0.001). No significant between-group differences in hepatic superoxide dismutase or catalase activities were found. Compared with controls (14.5 [1.9] μg collagen/mg protein), the mean (SE) histologic hepatic collagen concentration was significantly higher in all groups (19.2 [1.2], 19.5 [3.3], 18.5 [3.0], 25.9 [3.3], and 21.6 [1.5] μg collagen/mg protein in the LDetvitE, LDetvitC, LDetvitEC, LDet, and LDS groups, respectively; P<0.01, P<0.01, P<0.05, P<0.001, and P<0.001, respectively). Compared with the LDet group, the mean hepatic collagen concentration was significantly lower in the LDetvitE, LDetvitC, and LDetvitEC groups (P<0.01, P<0.05, and P<0.01, respectively). The LDetvitEC group had a significantly lower mean (SE) hepatic inflammatory score compared with the LDet group (0.8 [0.1] vs 1.3 [0.2]; P<0.05). The LDetvitEC group had a significantly lower mean (SE) hepatic necrosis score compared with that in the LDet group (1.5 [0.2] vs 2.4 [0.3]; P<0.05).

CONCLUSIONS

The results of this study in protein-deficient rats fed with a high-fat liquid diet suggest that supplementation with vitamin E, vitamin C, and a combination of vitamins E and C was associated with decreased ethanol-induced hepatic glutathione peroxidase activity and hepatic fibrosis, and that supplementation with vitamins E and C might have attenuated the development of hepatomegaly and hepatic necroinflammation, whereas this result was not found in the group given a liquid diet and ethanol in this 8-week study. (Curr Ther Res Clin Exp. 2006;67:118-137) Copyright © 2006 Excerpta Medica, Inc.

Ascorbic acid suppresses endotoxemia and NF-κB signaling cascade in alcoholic liver fibrosis in guinea pigs: a mechanistic approach

Alcohol consumption increases the small intestinal bacterial overgrowth (SIBO) and intestinal permeability of endotoxin. The endotoxin mediated inflammatory signaling plays a major role in alcoholic liver fibrosis. We evaluated the effect of ascorbic acid (AA), silymarin and alcohol abstention on the alcohol induced endotoxemia and NF-κB activation cascade pathway in guinea pigs (Cavia porcellus). Guinea pigs were administered ethanol at a daily dose of 4g/kg b.wt for 90days. After 90days, ethanol administration was stopped. The ethanol treated animals were divided into abstention, silymarin (250mg/kg b.wt) and AA (250mg/kg b.wt) supplemented groups and maintained for 30days. The SIBO, intestinal permeability and endotoxin were significantly increased in the ethanol group. The mRNA expressions of intestinal proteins claudin, occludin and zona occludens-1 were significantly decreased in ethanol group. The mRNA levels of inflammatory receptors, activity of IKKβ and the protein expressions of phospho-IκBα, NF-κB, TNF-α, TGF-β1 and IL-6 were also altered in ethanol group. The expressions of fibrosis markers α-SMA, α1 (I) collagen and sirius red staining in the liver revealed the induction of fibrosis. But the supplementation of AA could induce greater reduction of ethanol induced SIBO, intestinal barrier defects, NF-κB activation and liver fibrosis than silymarin. The possible mechanism may be the inhibitory effect of AA on SIBO, intestinal barrier defect and IKKβ, which decreased the activation of NF-κB and synthesis of cytokines. This might have led to suppression of HSCs activation and liver fibrosis.

Ascorbic acid is superior to silymarin in the recovery of ethanol-induced inflammatory reactions in hepatocytes of guinea pigs

Both oxidative stress and inflammatory reactions play a major role in alcoholic liver fibrosis. We evaluated the efficacy of ascorbic acid (AA) and silymarin in the regression of alcohol-induced inflammation in hepatocytes of guinea pigs (Cavia porcellus). Animals were administered with ethanol at a daily dose of 4 g/kg body weight (b.wt) for 90 days. On the ninety-first day, ethanol administration was stopped and animals were divided into alcohol abstention group and silymarin- (25 mg/100 g b.wt) and AA- (25 mg/100 g b.wt) supplemented groups and maintained for 30 days. There was a significant increase in the activities of alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase in the serum of the ethanol group. The intracellular reactive oxygen species (ROS) and expressions of cytochrome P4502E1 and nuclear factor κB1, tumor necrosis factor-α, and transforming growth factor-β(1) in hepatocytes were significantly increased in ethanol group. The fibrotic markers α-smooth muscle actin and α(1)(I) collagen and activity of cytotoxicity marker caspase-3 were significantly increased and AA content was significantly reduced in hepatocytes of alcohol-treated guinea pigs. But the AA and silymarin supplementation significantly reduced these changes in comparison with alcohol abstention group. AA could induce greater reduction of inflammatory and fibrotic markers in hepatocytes than silymarin. This indicates that AA is superior to silymarin in inhibiting intracellular ROS generation and thereby reducing the ethanol-induced inflammation in hepatocytes.

Gastroprotective effects of Leejung-tang, an oriental traditional herbal formula, on ethanol-induced acute gastric injury in rats

Leejung-tang (LJT, Rechu-to in Japanese and Lizhong-tang in Chinese) is an oriental traditional traditional herbal formula. LJT has been used for treatment of gastrointestinal disorders in Korea, Japan, and China for a long time. In present study, we investigated the protective effects of LJT against absolute ethanol induced gastric injuries. Rats in the control group were given PBS orally (5 mL/kg body weight) as the vehicle, and the absolute-ethanol group (EtOH group) received absolute ethanol (5 mL/kg body weight) by oral gavage. Rats in the positive control group were given omeprazole orally (50 mg/kg body weight) 2 h prior to the administration of absolute ethanol. The treatment groups received LJT (400 mg/kg body weight) 2 h prior to absolute ethanol administration. All rats were sacrificed 1 h after receiving the ethanol treatment. The stomach was excised for macroscopic examination and biochemical analysis. The administration of LJT protected gastric mucosa against ethanol-induced acute gastric injury, including hemorrhage and hyperemia. LJT reduced the increase in lipid peroxidation in ethanol-induced acute gastric lesions. LJT increased GSH content and activities of the antioxidant enzymes, catalase, glutathione-S-transferase, glutathione reductase, glutathione peroxidase, and superoxide dismutase. These results indicate that LJT protects gastric mucosa against ethanol-induced acute gastric injury by increasing their antioxidant content. We suggest that LJT can be developed as an effective drug for the treatment of acute gastric injury.

Biochemical and immunological basis of silymarin effect, a milk thistle (Silybum marianum) against ethanol-induced oxidative damage

Ethanol metabolism induces generation of excessive amount of reactive oxygen species (ROS) which results in immune dysfunction. We examined the efficacy of silymarin on ethanol-induced oxidative stress, immunomodulatory activity, and vascular function in mice blood. Effectiveness of silymarin was compared with potent antioxidant ascorbic acid. In the present study, 8- to 10-week-old male BALB/c mice (20-30 g) were divided into the four groups of six each. One group were fed with ethanol (1.6 g/kg body weight), while second group were fed with ethanol (1.6 g/kg body weight) and silybin (250 mg/kg body weight), and the third group were exposed to ethanol (250 mg/kg body weight) and ascorbic acid (250 mg/kg body weight) per day for 12 weeks. The control group was fed with isocaloric glucose solution instead of ethanol. Ethanol exposure significantly increased thiobarbituric acid reactive substance (TBARS) and nitrite levels besides glutathione-S-transferase (GST) activity, and significantly decreased reduced glutathione (GSH) content and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx) in whole blood hemolyzate, while silymarin treatment significantly normalized these altered parameters. Silymarin significantly prevented ethanol-induced, elevated activities of interleukin (IL)-10, tumor necrosis factor (TNF)-α, γ interferon (IFN-γ), vascular endothelial growth factor (VEGF)-A, and transforming growth factor (TGF)-β1, as well as decreased IL-4 activity in mice blood. These results were comparable with the activity of ascorbic acid.

Ascorbic acid supplementation down-regulates the alcohol induced oxidative stress, hepatic stellate cell activation, cytotoxicity and mRNA levels of selected fibrotic genes in guinea pigs

Both oxidative stress and endotoxins mediated immunological reactions play a major role in the progression of alcoholic hepatic fibrosis. Ascorbic acid has been reported to reduce alcohol-induced toxicity and ascorbic acid levels are reduced in alcoholics. Hence, we investigated the hepatoprotective action of ascorbic acid in the reversal of alcohol-induced hepatic fibrosis in male guinea pigs (n = 36), and it was compared with the animals abstenting from alcohol treatment. In comparison with the alcohol abstention group, there was a reduction in the activities of toxicity markers and levels of lipid and protein peroxidation products, expression of α-SMA, caspase-3 activity and mRNA levels of CYP2E1, TGF-β(1), TNF-α and α(1)(I) collagen in liver of the ascorbic acid-supplemented group. The ascorbic acid content in liver was significantly reduced in the alcohol-treated guinea pigs. But it was reversed to normal level in the ascorbic acid-supplemented group. The anti-fibrotic action of ascorbic acid in the rapid regression of alcoholic liver fibrosis may be attributed to decrease in the oxidative stress, hepatic stellate cells activation, cytotoxicity and mRNA expression of fibrotic genes CYP2E1, TGF-β(1), TNF-α and α(1) (I) collagen in hepatic tissues.

Ascorbic acid supplementation causes faster restoration of reduced glutathione content in the regression of alcohol-induced hepatotoxicity in male guinea pigs

Alcoholic liver disease is caused mainly by free radicals. Ascorbic acid (AA) and glutathione (GSH) are the major water-soluble antioxidants in the liver. The impact of AA supplementation on GSH, AA and activities of GSH-dependent enzymes in alcoholic guinea pigs was studied and was compared with alcohol abstention. Guinea pigs were administered ethanol at a dose of 4 g/kg body weight (b.wt)/day for 90 days. After 90 days, alcohol administration was stopped and one-half of the ethanol-treated animals were supplemented with AA (25 mg/100 g b.wt) for 30 days and the other half was maintained as the abstention group. There was a significant increase in the activities of alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transpeptidase in the serum of the ethanol group. In addition, a significant decrease in the GSH content, activities of GSH peroxidase, GSH reductase, and increased activity of GSH-S-transferase were observed in the liver of the ethanol group. Histopathological analysis and triglycerides content in the liver of the ethanol group showed induction of steatosis. But AA supplementation and abstention altered the changes caused by ethanol. However, maximum protective effect was observed in the AA-supplemented group indicating the ameliorative effect of AA in the liver.

Effect of melatonin and vitamin C on expression of endothelial NOS in heart of chronic alcoholic rats

The aim of this study was to investigate the effects of melatonin and vitamin C on expression of endothelial nitric oxide synthase (NOS) in heart tissue of chronic alcoholic rats. Twenty-four adult male Wistar rats weighing 200-250 g were used in this study. Rats were divided into four groups. The first group served as control (n = 6). The second group was treated with ethanol (%7.2) for 28 days (n = 6), which was administered in artificial isocaloric diets. The third group was given ethanol and supplemented with 40 mg/kg vitamin C [intraperitoneally (i.p.)] (n = 6). The fourth group was given ethanol and supplemented with 4 mg/kg melatonin (i.p.) (n = 6). At the end of the experiment, rats were sacrificed and heart tissues were processed for immunohistochemistry analysis to endothelial NOS (eNOS). eNOS immunoreactivity showed heterogeneous distribution in control group. eNOS immunoreactivity was (+) in some myocytes and (++) in some others. Expression of eNOS in alcohol group was heterogeneous like control group but also stronger than that. Immunoreactivity was (+++) in myocytes near the epicardial zone and (++) in myocytes near the endocardium border. In melatonin and vitamin C-treated groups, eNOS immunoreactivity was diffuse and the intensity of reaction was (+++) in subepicardial region. However, eNOS immunoreactivity scores were weaker in these groups when compared with the alcohol group. Our results indicate that alleviation of oxidative stress by antioxidant therapy reduces reactive oxygen species-mediated nitric oxide inactivation.

Protective effects of cysteine, methionine and vitamin C on the stomach in chronically alcohol treated rats

A chronic intake of high dose alcohol may cause oxidative stress and inflammation in the stomach. It is hypothesized that cysteine-methionine and vitamin C may neutralize harmful compounds while potentiating the antioxidant capacity of the cell or tissue. The experimental animals were fed regular diets and were maintained for 90 days in the control group, the alcoholic group, which was given 2.5 g of 50% ethanol kg(-1) body wt. administered intragastrically every other day, or the alcoholic with antioxidant supplement group, to whom 2.5 g of 50% ethanol kg(-1) body wt. + a solution that contained 200 mg vitamin C, 100 mg cysteine and 100 mg methionine was administered intragastrically every other day. After the treatments, the stomach was taken for pathological and biochemical analysis. The stomach of the alcoholic group rats had higher scores of pathological findings compared with the control group, whereas the scores of the antioxidant-supplemented group were lower than the alcoholic group. In addition, the oxidized protein and lipid content in the stomachs of the alcoholic group were significantly higher than the control, but antioxidant supplementation lowered the amount of oxidation in the antioxidant supplemented group. The amount of stomach glutathione in the alcoholic group was higher than that of the control and antioxidant-supplemented groups. Interestingly, the level of total thiol in the stomach tissue of rats with antioxidant supplement was statistically higher than that of the control and alcoholic groups. In conclusion, the scores of the pathological findings in the stomach of rats with the antioxidant supplement were lower than the chronic alcohol-treated rats, albeit the amount of total thiol was increased in this group. Moreover, chronic alcohol treatment led to an increase in the level of lipid and protein oxidation in the stomach tissue of rats. A simultaneous intake of ascorbate/l-cys/l-met along with ethanol attenuated the amount of oxidation which suggested that cysteine-methionine and vitamin C could play a protective role in the stomach against oxidative damage resulting from chronic alcohol ingestion.

Combined effects of vitamin C, vitamin E, and sodium selenate supplementation on absolute ethanol-induced injury in various organs of rats

In this study, the effect of combination of vitamin C (ascorbic acid), vitamin E (alpha -tocopherol), and selenium (sodium selenate) on ethanol-induced liver and intestine injury in rats was investigated. The ethanol-induced injury was produced by the administration of 1 ml of absolute ethanol to each rats. Animals received vitamin C (250 mg/kg), vitamin E (250 mg/kg), and sodium selenate (Se) (0.5 mg/kg) for 3 days; 1 h after the final antioxidant administration, they were sacrificed. Lipid peroxidation and glutathione levels, catalase (CAT), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and glutathione peroxidase (GP(x)) activities were determined in liver and intestine tissues. Myeloperoxidase (MPO), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma-glutamyltransferase (GGT) were determined in liver tissue. Also, CAT activity, urea, creatinine, uric acid, and total lipid levels were determined in serum samples. In the ethanol group, serum urea, creatinine, uric acid, and total lipid levels; liver and intestine LDH; liver MPO, AST, ALP, ALT, and GGT activities; and liver and intestine LPO levels increased, whereas serum CAT activity, liver and intestine GSH levels, and CAT, SOD, and GP(x) activities decreased. On the other hand, treatment with vitamin C, vitamin E, and Se reversed these effects. As a result of these findings, we can say that the combination of vitamin C, vitamin E, and selenium has a protective effect on ethanol-induced changes in lipid peroxidation, glutathione levels, and antioxidant enzyme activities in liver and intestine tissues, and in some serum parameters of rats.

Effects of maternal administration of vitamins C and E on ethanol neurobehavioral teratogenicity in the guinea pig

Consumption of ethanol during human pregnancy can produce a wide spectrum of teratogenic effects, including neurobehavioral dysfunction. This study, in the guinea pig, tested the hypothesis that chronic maternal administration of antioxidant vitamins C plus E, together with ethanol, mitigates ethanol neurobehavioral teratogenicity. Pregnant guinea pigs received one of the following four chronic oral regimens: ethanol and vitamins C plus E; ethanol and vitamin vehicle; isocaloric-sucrose/pair-feeding and vitamins C plus E; or isocaloric-sucrose/pair-feeding and vehicle. Vitamins C (250 mg) plus E (100mg) or vehicle were given daily, and ethanol (4 g/kg maternal body weight/day) (E) or isocaloric-sucrose/pair-feeding was given for 5 consecutive days followed by 2 days of no treatment each week throughout gestation. One neonate from selected litters was studied on postnatal day (PD) 0. Neurobehavioral function was determined by measuring task acquisition and task retention using an 8-day moving-platform version of the Morris water-maze task, starting on PD 45. Thereafter, in vivo electrophysiologic assessment of changes in hippocampal synaptic plasticity was conducted. There was an ethanol-induced decrease in neonatal brain weight compared with sucrose. The vitamins C plus E regimen protected hippocampal weight relative to brain weight in ethanol offspring, and mitigated the ethanol-induced deficit in the task-retention component of the water-maze task. However, in the sucrose group, this Vit regimen produced deficits in both task acquisition and task retention. The vitamins C plus E regimen did not mitigate the ethanol-induced impairment of hippocampal long-term potentiation. These results indicate that maternal administration of this high-dose vitamins C plus E regimen throughout gestation has limited efficacy and potential adverse effects as a therapeutic intervention for E neurobehavioral teratogenicity.

The effect of zymosan and the protective effect of various antioxidants on fracture healing in rats

AIM

To investigate the effects of free oxygen radicals and various antioxidants on bone healing after experimental formation of fracture.

MATERIALS AND METHODS

Fifty male rats were used and divided into five groups (ten rats in each). The right forelimbs of the rats were broken by bimanual compression method. One hour before this procedure, 5 ml/kg of intraperitoneal (i.p.) physiologic saline were given to the control Group 1. All 40 rats in the experimental Groups 2, 3, 4 and 5 were treated with i.p. zymosan at a dosage of 100 mg/kg to induce the production of free radicals by stimulating NADPH oxidase in polymorphonuclear leukocytes. Zymosan induction was stopped on the fifth post-fracture day. In addition to the zymosan, i.p. 1 g/kg/day of dimethyl sulfoxide were given to the animals in Group 3, 50 mg/kg/d of Ginko biloba Extract (EGb 761) in Group 4 and 500 mg/kg/day of vitamin C in Group 5. Radiographs of the fractures of all animals were obtained to assess callus formation, remodeling and bridging bone formation under ether anesthetics on postfracture day 7, 14 and 21. All rats were euthanized on day 22, and sections of the radius and ulna were examined both histologically with light and electron microscopy and ultrastructurally. Statistical analysis was made with Kruskal-Wallis variance analyze test and comparison between groups was performed by Dunn's multiple comparison test.

RESULTS

An impairment of bone healing was observed in Group 2 inducted with purely zymosan. Variable results were obtained for bone healing in the groups treated with various antioxidants. There was very significant difference of fracture healing between Groups 1 and 2 both histologically and radiologically (P < 0.001). There was significant difference between Groups 2 and 5 radiologically (P < 0.05).

CONCLUSION

Free oxygen radicals demonstrate a negative effect on fracture healing and vitamin C (an antioxidant) partially prevents the negative effect of zymosan on fracture healing.

Influence of zinc sulfate intake on acute ethanol-induced liver injury in rats

AIM: To investigate the role of metallothionein and proliferating cell nuclear antigen (PCNA) on the morphological and biochemical effects of zinc sulfate in ethanol-induced liver injury.

METHODS: Wistar albino rats were divided into four groups. Group I; intact rats, group II; control rats given only zinc, group III; animals given absolute ethanol, group IV; rats given zinc and absolute ethanol. Ethanol-induced injury was produced by the 1 mL of absolute ethanol, administrated by gavage technique to each rat. Animals received 100 mg/kg per day zinc sulfate for 3 d 2 h prior to the administration of absolute ethanol.

RESULTS: Increases in metallothionein immunoreactivity in control rats given only zinc and rats given zinc and ethanol were observed. PCNA immunohistochemistry showed that the number of PCNA-positive hepatocytes was increased significantly in the livers of rats administered ethanol + zinc sulfate. Acute ethanol exposure caused degenerative morphological changes in the liver. Blood glutathione levels decreased, serum alkaline phosphatase and aspartate transaminase activities increased in the ethanol group when compared to the control group. Liver glutathione levels were reduced, but lipid peroxidation increased in the livers of the group administered ethanol as compared to the other groups. Administration of zinc sulfate in the ethanol group caused a significant decrease in degenerative changes, lipid peroxidation, and alkaline phosphatase and aspartate transaminase activities, but an increase in liver glutathione.

CONCLUSION: Zinc sulfate has a protective effect on ethanol-induced liver injury. In addition, cell proliferation may be related to the increase in metallothionein immunoreactivity in the livers of rats administered ethanol + zinc sulfate.

Tissue-specific effect of ascorbic acid supplementation on the expression of cytochrome P450 2E1 and oxidative stress in streptozotocin-induced diabetic rats

Here, we investigated the effect of l-ascorbic acid (AA) supplementation on the CYP2E1 expression level and oxidative stress in various tissues such as the liver, kidney, pancreas, and brain of streptozotocin (STZ)-induced diabetic rats. An increased cytochrome P450 2E1 (CYP2E1) expression level with a concomitant increase in the production of reactive oxygen species were found in all the tissues of STZ-induced diabetic rats tested compared with an untreated control, suggesting the possible diabetes-induced tissue injury. In contrast, the AA supplementation to the diabetic rats alleviated these experimental parameters in a tissue-specific manner. AA affected the liver most severely followed by the kidney. There was little or no effect of AA supplementation on the brain and pancreas. The circulation level of the ketone bodies, inducers of CYP2E1, was also decreased by AA supplementation compared with those of the diabetic rats. Therefore, the suppression of ketone production by AA can be one of the mechanisms of a reduction in CYP2E1. These results suggest that AA plays an important role in reducing elevated CYP2E1 expression level and the oxidative stress mediated by type 1 diabetes with a tissue-specific variation.

Orange juice ingestion and supplemental vitamin C are equally effective at reducing plasma lipid peroxidation in healthy adult women

OBJECTIVE

To directly examine the contribution of vitamin C to the antioxidant potential of fruits and vegetables, the antioxidant effect of orange juice consumption (8 and 16 fl. oz.) was compared to the antioxidant effect of supplemental vitamin C (dosage equivalent to that supplied by 8 fl. oz. of orange juice).

METHODS

Subjects (n = 11; 28.6 +/- 2.1 years) received each treatment in a 3 x 3 randomized crossover design, and each two-week treatment was preceded by a two-week washout. During the entire trial, subjects restricted fruit and vegetable consumption to < or =3 servings per day except the vitamin C-rich foods (items containing >20 mg/serving), which were restricted to < or =3 servings per week. A fasting blood sample was collected at the end of each washout and each treatment period.

RESULTS

Following washouts, plasma vitamin C and lipid peroxidation (plasma TBARS) were similar by treatment group and averaged 25.4 +/- 3.6 micromol/L and 3.82 +/- 0.10 nmol/mL respectively. Plasma vitamin C concentrations were similar following each treatment period, 37.9 +/- 8.1, 45.8 +/- 9.4, and 38.3 +/- 12.4 micromol/L for the 8 and 16 fl. oz. orange juice treatments and the supplement treatment, respectively. All intervention treatments reduced plasma TBARS as compared to pretreatment values: -47% (p = 0.013), -40% (p = 0.083), and -46% (p = 0.015) for the 8 and 16 fl. oz. orange juice treatments and supplement treatment respectively.

CONCLUSIONS

These data indicate that the regular consumption of 8 fl. oz. orange juice or supplemental vitamin C ( approximately 70 mg/day) effectively reduced a marker of lipid peroxidation in plasma.

The water extract of Omija protects H9c2 cardiomyoblast cells from hydrogen peroxide through prevention of mitochondrial dysfunction and activation of caspases pathway

The water extract of Omija (Omija) has been used traditionally in the treatment of ischemic damage of the heart and brain tissues. However, little is known about the mechanism by which it rescues myocardial cells from oxidative stress. This study was designed to investigate the protective mechanisms of Omija on H(2)O(2)-induced cytotoxicity in H9c2 cardiomyoblast cells. Treatment with H(2)O(2) resulted in the death of H9c2 cells, characterized by apparent apoptotic features, including fragmentation of the nucleus and an increase in the sub-G(0)/G(1) fraction of the cell cycle. However, Omija markedly suppressed the apoptotic characteristics of H9c2 cells induced by H(2)O(2). In addition, Omija suppressed the features of mitochondrial dysfunction, including changes in the mitochondrial membrane potential and cytosolic release of cytochrome c in H(2)O(2)-treated cells. Treatment with Omija further inhibited the catalytic activation of caspase-9 and caspase-3 and induction of Fas by H(2)O(2). Taken together, these data indicate that the water extract of Omija protects H9c2 cardiomyoblast cells from oxidative stress of H(2)O(2) through inhibition of mitochondrial dysfunction and activation of intrinsic caspase cascades, including caspase-3 and caspase-9.

Non-invasive monitoring of oxidant stress in alcoholic liver disease

OBJECTIVE

In alcoholic liver disease (ALD), progression from initial steatosis, through hepatitis to cirrhosis is well described, resulting in 20,000 deaths in the UK annually. However, pathological mechanisms are not well understood and drug trials have led to conflicting results. It has been established that alcohol consumption increases hepatic free radical production and oxidant stress has been implicated in the disease process.

MATERIAL AND METHODS

Markers of lipid peroxidation, antioxidant status, hepatic fibrogenesis, inflammation and liver function were measured in blood and urine from 24 patients with established alcoholic cirrhosis and in 49 age- and sex-matched controls.

RESULTS

In the ALD group, lipid peroxidation markers 8-isoprostane and malondialdehyde were significantly increased (p<0.001), as was the ratio of oxidized to reduced glutathione (p=0.027). The antioxidants selenium, glutathione (whole blood and plasma) and vitamins A, C and E were all significantly decreased (p<0.001); median plasma glutathione levels were only 19% of control levels. Type III procollagen peptide (PIIINP), a serum marker of hepatic fibrogenesis, and C-reactive protein (CRP) were both increased (p<0.001). Urinary 8-isoprostane correlated positively with PIIINP, CRP and markers of cholestasis (alkaline phosphatase and bilirubin) and negatively with glutathione (whole blood), vitamins A and E and albumin.

CONCLUSIONS

Oxidant stress, as reflected in blood and urine by a wide range of pro- and antioxidant markers, is a significant feature of alcoholic cirrhosis, providing a mechanism by which alcohol intake may be linked to hepatic inflammation and fibrosis. Non-invasive markers could prove valuable in monitoring response to treatment during clinical trials.

The protective effect of vitamin C, vitamin E and selenium combination therapy on ethanol-induced duodenal mucosal injury

In this study, the effect of a combination of vitamin C, vitamin E and selenium on ethanol-induced duodenal mucosal damage in rats was investigated morphologically and biochemically. The duodenal mucosal injury was produced by oral administration of 1 mL of absolute ethanol to each rat. Animals received vitamin C (250 mg/ kg), vitamin E (250 mg/kg) and selenium (0.5 mg/kg) for 3 days and absolute ethanol 1 hour after last antioxidant administration and were sacrificed 1 hour after absolute ethanol. Extreme degeneration in intestinal mucosa of rats given ethanol was observed morphologically. In addition, an increase in neuronal nitric oxide synthase immunoreactive areas was observed in the rats of the group given ethanol. On the other hand, a normal morphological appearance and a decrease in neuronal nitric oxide synthase immunoreactive areas were detected in the rats given ethanol+vitamin C+vitamin E+ selenium. In the group to which ethanol was administered, an increase in serum cholesterol and a decrease in serum albumin levels were determined. On the other hand, in the group to which ethanol+vitamin C+vitamin E+selenium were administered, serum cholesterol value decreased, and the serum albumin level increased. As a result, we can say that the combination of vitamin C, vitamin E and selenium has a protective effect on ethanol-induced duodenal mucosal injury.

Oxidative Stress and Apoptosis in Cardiomyocyte Induced by High-Dose Alcohol

Binge drinking of alcohol causes cardiac dysfunction in some people. The mechanism remains unclear. This study was designed to investigate high doses of alcohol-induced oxidative stress and apoptosis in cardiomyocytes and protective effects of antioxidants. Cardiomyocytes isolated from 1- to 2-day-old Sprague-Dawley rats were treated with ethanol at doses of 0 mM, 50 mM, 100 mM, and 200 mM for 24 hours. Vitamin E (1 mM) and vitamin C (0.2 mM) were added to medium 1 hour before addition of ethanol. Results showed typical apoptosis: chromatin condensation, membrane blebbing, shrinkage, and cytoplasm condensation. Apoptosis is concentration-dependent in the range of 0 to 100 mM ethanol (apoptosis rates were respectively 0.68%, 2.03%, and 9.66% at ethanol concentration of 0 mM, 50 mM, and 100 mM). Necrotic cells became greatly increased in the 200 mM ethanol-treated group. Intracellular production of reactive oxygen intermediates increased as mitochondrial membrane potential decreased after ethanol treatment. Cytochrome c was found to be greater in the cytosol of the ethanol-treated groups. Activity of caspase-3 was higher in ethanol-treated groups (P < 0.05). Both vitamin E and vitamin C inhibited oxidative stress and myocyte apoptosis in ethanol-treated groups (P < 0.05). In conclusion, our data indicated that acute high-dose ethanol treatment primarily induces cardiomyocyte apoptosis at concentration up to 100 mM while necrosis is predominate at 200 mM. The underlying mechanism appears to involve mitochondrial damage via an increase in oxidative stress and releasing cytochrome c, which activates caspases that initiate chromatin fragmentation and apoptosis. Antioxidants, to a large extent, inhibit oxidative stress and apoptosis induced by ethanol.

Effect of systemic vitamin C on free fatty acid-induced lipid peroxidation

OBJECTIVES

Plasma malondialdehyde (MDA), a reactive product of lipid peroxidation, may be influenced by anti-oxidant therapy. The aim of the present study was to investigate if elevated MDA as induced by increased free fatty acids (FFA) correlates with endothelial function and is affected by high doses of vitamin C.

METHODS

The study design was randomised, placebo-controlled, double blind, 2-way cross over. Plasma MDA concentrations and forearm blood flow (FBF) responses to intra-arterial acetylcholine (ACh) and glyceryl trinitrate were assessed during co-administration of vitamin C or placebo in the presence of increased plasma FFA by Intralipid/heparin infusion in 10 healthy male subjects.

RESULTS

The seven-fold rise in plasma FFA was associated with an increase in plasma MDA concentrations (r=0.7, p<0.001) and decreased FBF responses to ACh (r=-0.4, p<0.01). Co-administration of vitamin C restored the impaired reactivity of FBF to ACh but had no effect on elevated MDA concentrations.

CONCLUSIONS

Anti-oxidant vitamin C improves lipid-induced impairment of endothelium-dependent vasodilation, but does not alter MDA formation or breakdown.

Combined effect of ascorbic acid and selenium supplementation on alcohol-induced oxidative stress in guinea pigs

Oxidative stress is a key step in the pathogenesis of ethanol associated liver injury. Ethanol administration induces an increase in lipid peroxidation either by enhancing the production of oxygen reactive species or by decreasing the level of endogenous antioxidants. In this present study, four groups of male guinea pigs (Cavia porcellus) were maintained for 45 days as follows: Control group (1 mg ascorbic acid (AA)/100 g body wt./day); Ethanol group (1 mg AA/100 g body wt./day+900 mg ethanol/100 g body wt./day); Selenium+AA group (25 mg AA+0.05 mg sodium selenite/100 g body wt./day); Ethanol+Se+AA group (25 mg AA+0.05 mg sodium selenite/100 g body wt.+900 mg ethanol/100 g body wt./day). Malondialehyde (MDA), hydroperoxides (HP) and conjugated dienes (CD) were significantly increased, while the activities of scavenging enzymes superoxide dismutase (SOD) and catalase were reduced in the alcohol administered groups. Co-administration of Se+AA along with alcohol increased the activities of scavenging enzymes and reduced the lipid peroxidation products level in hepatic tissues of guinea pigs. Activities of glutathione peroxidase (GPX) and glutathione reductase (GR) were enhanced in co-administered group. gamma-Glutamyl transpeptidase (GGT), a marker enzyme of alcohol induced toxicity, was also reduced, as was the glutathione content. This study suggests that the combined effect of Se+AA, provides protection against alcohol-induced oxidative stress as evidenced from the decreased levels of lipid peroxidation products and enhanced activities of scavenging enzymes.

Effect of zinc on hepatic lipid peroxidation and antioxidative enzymes in ethanol-fed rats

A 3-ml aliquot of 30% ethanol was fed daily to normal as well as zinc-treated (227 mg l(-1)) rats for periods of 2, 4 and 8 weeks. A highly significant increase in the levels of hepatic lipid peroxidation was observed in ethanol-fed rats after 4 and 8 weeks of treatment. On the other hand, the levels of lipid peroxidation came down significantly following ethanol feeding to zinc-treated rats. The activities of glutathione peroxidase (GPx), catalase and superoxide dismutase (SOD) in liver were elevated significantly after ethanol administration to rats for durations of 2, 4 and 8 weeks. Interestingly, zinc treatment to rats given ethanol was able to bring down the elevated levels of SOD, catalase and GPx to within normal limits, However, zinc administration alone did not cause any significant alteration in the activities of these antioxidative enzymes.

Cytotoxicity of amino alcohols to rat hepatoma-derived Fa32 cells

Amino alcohols are used as emulsifying agents in dry-cleaning soaps, wax removers, cosmetics, paints and insecticides. The cytotoxicities of 12 amino alcohols, which differed in chain length, position of the amino and alcohol groups, and the presence of an additional phenyl group, were determined by the neutral red uptake inhibition assay with normally cultured, glutathione-depleted or antioxidant-enriched Fa32 rat hepatoma-derived cells. Glutathione depletion and antioxidant enrichment were achieved by including 50(M L-buthionine-S,R-sulphoximine (BSO) or 100(M (-tocopherol acetate (vitamin E) in the culture medium for 24 hours before and during the assay. The cytotoxicity of the amino alcohols observed after treatment for 24 hours was expressed as the concentration of compound needed to induce a 50% reduction in neutral red uptake (NI50). The observed NI50 values ranged from 3mM to 30mM. The individual stereoisomers and a racemic mixture of 1-amino-2-propanol exhibited similar cytotoxicities (with normally cultured Fa32 cells, and vitamin E- and BSO-treated cultures). Similar NI50 values for D-(+)-2-amino-1-propanol, 3-amino-1-propanol and the L-, D- or DL- forms of 1-amino-2-propanol, indicated that the position of the amino group had little influence on the cytotoxicities of the amino alcohols. In contrast, the position of the hydroxyl group appeared to play an important role for the toxicity of the compound, as indicated by the significantly different NI50 values for 4-amino-1-butanol and 4-amino-2-butanol. An additional phenyl group greatly increased the cytotoxicity of 2-amino-1,3-propanediol. For most of the compounds, cytotoxicity increased when GSH was depleted, and decreased when the cells were enriched with vitamin E. This indicated that most of the tested chemicals interact with GSH, either directly or indirectly, by processes which generate oxygen free-radicals. Decreased toxicity was found for most of the chemicals administered to vitamin E-enriched cells, indicating that reactive oxygen species could be involved in the toxicity of the amino alcohols.

Enhanced heme oxygenase activity increases the antioxidant defense capacity of guinea pig liver upon acute cobalt chloride loading: comparison with rat liver

Changes in the activity of so-called oxidative stress defensive enzymes, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and heme oxygenase, as well as changes in lipid peroxidation and reduced glutathione levels, were measured in guinea pig and rat liver after acute cobalt loading. Cobalt chloride administration produced a much higher degree of lipid peroxidation in guinea pig than in rat liver compared with the control animals. The intrahepatic reduced glutathione content in control guinea pig was higher than that in rat, but was equally decreased in both species after cobalt administration. The enzymatic scavengers of free radicals, superoxide dismutase, catalase and glutathione peroxidase, were significantly decreased in rat liver after acute cobalt loading, and as a compensatory reaction, the heme oxygenase activity was increased (seven-fold). In guinea pig liver, only superoxide dismutase activity was depleted in response to cobalt-induced oxidative stress, while catalase and glutathione peroxidase were highly activated and the heme oxygenase activity was dramatically increased (13-fold). It is assumed that enhanced heme oxygenase activity may have important antioxidant significance by increasing the liver oxidative-stress defense capacity.

Guinea pigs as models for cholesterol and lipoprotein metabolism

Guinea pigs carry the majority of their plasma cholesterol in LDL, making them a unique animal model with which to study hepatic cholesterol and lipoprotein metabolism. In this review, the benefits and advantages of using this particular model are discussed. How dietary factors such as soluble fiber, cholesterol and fatty acids that vary in saturation and chain length affect hepatic cholesterol homeostasis and influence the synthesis, intravascular processing and catabolism of lipoproteins is reviewed. In addition, alterations in hepatic cholesterol metabolism and plasma lipoproteins as affected by treatment with cholestyramine or 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors, exercise, marginal intake of vitamin C, ovariectomy (a model for menopause) and similarities to the human situation are addressed. A review of guinea pigs as models for early atherosclerosis development is also presented.