Effect of ethanol in vivo on enzymes which detoxify oxygen free radicals

Camellia sinensis (L.) Kuntze Extract Ameliorates Chronic Ethanol-Induced Hepatotoxicity in Albino Rats

The goal of this study was to investigate the hepatoprotective effects of aqueous extract of Camellia sinensis or green tea extract (AQGTE) in chronic ethanol-induced albino rats. All animals were divided into 4 groups in the study for a 5-week duration. 50% ethanol was given orally to the rats with two doses (5 mg/kg bw and 10 mg/kg bw) of AQGTE. Ethanol administration caused a significant increase in the levels of plasma and serum enzymatic markers, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), and nonenzymatic markers (cholesterol and triglycerides), lipid peroxidation contents, malondialdehyde (MDA), and glutathione-S-transferase (GST), and decreased the activities of total proteins, albumin, and cellular antioxidant defense enzymes such as superoxide dismutase (SOD). The elevation and reduction in these biochemical enzymes caused the damage in hepatocytes histologically due to the high production of ROS, which retards the antioxidant defense capacity of cell. AQGTE was capable of recovering the level of these markers and the damaged hepatocytes to their normal structures. These results support the suggestion that AQGTE was able to enhance hepatoprotective and antioxidant effects in vivo against ethanol-induced toxicity.

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.

Brain Levels of Catalase Remain Constant through Strain, Developmental, and Chronic Alcohol Challenges

Catalase (EC 1.11.1.6) oxidizes ethanol to acetaldehyde within the brain and variations in catalase activity may underlie some consequences of ethanol consumption. The goals of this study were to measure catalase activity in subcellular fractions from rat brain and to compare the levels of this enzyme in several important settings. In the first series of studies, levels of catalase were compared between juvenile and adult rats and between the Long-Evans (LE) and Sprague-Dawley (SD) strains. Levels of catalase appear to have achieved the adult level by the preadolescent period defined by postnatal age (P, days) P25–P28, and there were no differences between strains at the developmental stages tested. Thus, variation in catalase activity is unlikely to be responsible for differences in how adolescent and adult rats respond to ethanol. In the second series of studies, periadolescent and adult rats were administered ethanol chronically through an ethanol-containing liquid diet. Diet consumption and blood ethanol concentrations were significantly higher for periadolescent rats. Catalase activities remained unchanged following ethanol consumption, with no significant differences within or between strains. Thus, the brain showed no apparent adaptive changes in levels of catalase, even when faced with the high levels of ethanol consumption characteristic of periadolescent rats.

In vitro and in vivo studies on the antioxidant activity of fish peptide isolated from the croaker (Otolithes ruber) muscle protein hydrolysate

Peptide from croaker (Otolithes ruber) muscle protein hydrolysate was purified, characterized and evaluated for its in vitro and in vivo antioxidant activity. Results showed that purified peptide contained the amino acid sequence as Lys-Thr-Phe-Cys-Gly-Arg-His (861.6Da), which were expected to contribute to its antioxidant activities. This peptide efficiently quenched 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals (84.5±1.2 and 62.4±2.9%), and successfully inhibits the lipid peroxidation and DNA damage and proven to be a potent antioxidant at different in vitro systems. It also improved the endogenous cellular antioxidant enzymes in Wistar rat by increasing the activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) after supplementation of the peptide (283.6±7.25, 4.3±0.78 and 28.42±1.97) compared to the negative control (196.4±5.65, 1.3±0.45 and 15.1±0.35). Therefore, croaker muscle peptide can increase an endurance capacity and facilitate recovery from oxidative stress.

Antioxidative status of patients with alcoholic liver disease in southeastern Taiwan

AIM: To investigate the antioxidative status of patients with alcoholic liver disease (ALD) in southeastern Taiwan.

METHODS: Our study comprised 27 patients with ALD recruited from Taitung Mackay Memorial Hospital, located in southeastern Taiwan. Patients with ALD included 12 non-aborigines (12 men) and 15 aborigines (11 men and 4 women). According to the severity of ALD, patients with ALD included 10 with hepatitis (9 men and 1 woman) and 17 with cirrhosis (14 men and 3 women). Twenty-two age- and gender-matched healthy adults served as the control group in this study. Venous blood (10 mL) of each subject was drawn into EDTA-containing tubes after 8 h overnight fasting.

RESULTS: Compared to the control group, patients with ALD showed significantly lower erythrocytic catalase (11.1 ± 0.7 U/mg Hb vs 8.0 ± 0.7 U/mg Hb, P < 0.05) and superoxide dismutase (9.5 ± 1.6 U/mg Hb vs 3.0 ± 0.2 U/mg Hb, P < 0.05) activities. Furthermore, the erythrocytic reduced glutathione/oxidized glutathione ratio was significantly lower in ALD patients than that in the control group (38.1 ± 5.4 vs 15.7 ± 1.9, P < 0.05). The results revealed that patients with ALD experienced more oxidative stress than those in the control group. The non-aboriginal, but not the aboriginal, ALD group had higher erythrocytic glutathione peroxidase (GPX) activity than that in the control group (46.1 ± 7.8 U/g Hb vs 27.9 ± 2.2 U/g Hb, P < 0.05). Hepatitis, but not cirrhosis, ALD patients had higher erythrocytic GPX activity than that in the control group (44.3 ± 8.6 U/g Hb vs 27.9 ± 2.2 U/g Hb, P < 0.05).

CONCLUSION: Our results indicate that both ethnicity and the severity of ALD may cause different erythrocytic antioxidative enzyme activities especially GPX activity.

The mechanism of elevated toxicity in HepG2 cells due to combined exposure to ethanol and ionizing radiation

Ethanol and ionizing radiation exposure are independently known to cause tissue damage through various mechanisms. The non-enzymatic and enzymatic metabolism of ethanol, the latter via the cytochrome P(450) 2E1-dependent pathway produces free radicals, which deplete cellular glutathione (GSH). Ionizing radiation exposure has been shown to induce lipid peroxidation, DNA damage, protein oxidation and GSH depletion. It was postulated that cells sensitized by ethanol will be susceptible to additional insult, such as by radiation through increased oxidative stress. In this investigation, cultured liver cells (HepG2, human hepatocellular liver carcinoma) were exposed to ethanol, followed by ionizing radiation. The antioxidant status of the cells was evaluated by an array of techniques. Levels of glutathione, cysteine (CYS), and malondialdehyde (MDA) were measured by HPLC. Activities of antioxidant enzymes, catalase and glutathione reductase (GR) were determined enzymatically. Apoptosis was evaluated by the caspases-3 assay and fluorescence microscopy. The data showed that combined treatment with ethanol and radiation resulted in the lowest levels of GSH, and highest MDA level compared with the control. The catalase activity was lower in the combined exposure groups, when compared with the single agent exposure groups, and the glutathione reductase activity was the highest in the combined exposure groups and lowest in the control. These findings suggest that a combination of ethanol and ionizing radiation results in greater toxicity in vitro through elevated oxidative stress.

Implication du stress oxydant dans la physiopathologie de la schizophrénie : revue de la literature

BACKGROUND

Schizophrenia is a devastating psychiatric disorder with a broad range of behavioural and biologic manifestations. There are several clinical characteristics of the illness that have been consistently associated with poor premorbid adjustment, long duration of psychosis prior to treatment and prominent negative symptoms. The etiopathogenic mechanisms of lack of insight in patients with schizophrenia are to date unknown, although several hypotheses have been suggested. A point of convergence for the theoretical models occurs with regard to the neuronal membrane. Neuronal membrane contains a high proportion of polyunsaturated fatty acid and is the site for oxidative stress. Oxidative stress is a state when there is unbalance between the generation of reactive oxygen species and antioxidant defence capacity of the body. It is closely associated with a number of diseases including Parkinson's disease, Alzheimer-type dementia and Huntington's chorea. Accumulating evidence points to many interrelated mechanisms that increase production of reactive oxygen or decrease antioxidant protection in schizophrenic patients.

OBJECTIVES

This review aims to summarize the perturbations in antioxidant protection systems during schizophrenia, their interrelationships with the characteristic clinics and therapeutics and the implications of these observations in the pathophysiology of schizophrenia are discussed.

LITERATURE FINDINGS

In schizophrenia there is evidence for deregulation of free radical metabolism, as detected by abnormal activity of critical antioxidant enzymes (superoxide dismutase, glutathione peroxidase and catalase). Many studies conclude in the decrease in the activity of key antioxidant enzymes in schizophrenia. A few studies have examined levels of non enzymatic antioxidants such as plasma antioxidant proteins (albumin, bilirubine, uric acid) and trace elements. How showed decreased levels in schizophrenic patients. Others studies have provided evidence of oxidative membrane damage by examining levels of lipid peroxidation products. Such abnormalities have been associated with certain clinical symptoms and therapeutic features. Negative symptoms have been associated with low levels of GSH-Px. Positive symptoms have been positively correlated with SOD activity. Plasma TAS was significantly lower in drug-free and haloperidol treated patients with schizophrenia. A low erythrocyte SOD activity has been found in never-treated patients, but with haloperidol treatment, SOD activity increased.

DISCUSSION

These results demonstrate altered membrane dynamics and antioxidant enzyme activity in schizophrenia. Membrane dysfunction can be secondary to free a radical-mediated pathology, and may contribute to specific aspects of the schizophrenia symptomatology. Membrane defects can significantly alter a broad range of membrane functions and presumably modify behavior through multiple downstream biological effects. Phospholipid metabolism in the brain may be perturbed in schizophrenia, with reduced amounts of phosphatidylcholins and phosphatidylethanolamine in post-mortem brain tissue from schizophrenic patients, and large amounts of lipofuscin-like materiel in the oligodendrocytes. The existence of these products within cell membranes results in an unstable membrane structure, altered membrane fluidity and permeability and impaired signal transduction. Recent findings suggest that multiple neurotransmitter systems may be faulty. CNS cells are more vulnerable to the toxic effects of free radicals because they have a high rate of catecholamine oxidative metabolic activity. Neurotransmitters, like glutamate, can induce the same metabolic processes that increase free radical production and can lead to impaired dopamine-glutamate balance. These results question the role of this imbalance in the biochemical basis evoked in the etipathogenic mechanisms of schizophrenia, as well as the role of antioxidants in the therapeutic strategy and their implication in preventive and early intervention approaches in populations at risk for schizophrenia.

Effects of beta-carotene on cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats

The purpose of the present study was to evaluate the effects of beta-carotene on the cell viability and antioxidant status of hepatocytes from chronically ethanol-fed rats. Rats in the ethanol group were given an ethanol-containing liquid diet that provided 36 % of total energy as ethanol, while rats in the control group were fed an isoenergetic diet without ethanol. After 4 weeks, hepatocytes were taken out and cultured for 24 h. Hepatocytes from the rats in the control and ethanol groups were cultured in medium without (HC, HE) or with beta-carotene (HC+B, HE+B). The results showed that lactate dehydrogenase leakage was significantly increased in the HE compared with that in the HC group. However, lactate dehydrogenase leakage of the HE+B group was similar to that of the HC group. When compared with the HC group, activities of glutathione peroxidase and catalase in the HE group were significantly decreased by 54 and 31 %, respectively. Catalase activity in the HE+B group was significantly increased by 61 % compared with that in the HE group. However, activities of glutathione reductase and superoxide dismutase showed no difference among the groups. The level of glutathione in the HC+B and HE+B groups was significantly increased to 155 and 143 % compared with those in the HC and HE groups, respectively. The concentration of lipid peroxides showed no difference among the groups. The present results demonstrate that beta-carotene improved the cell viability of hepatocytes, and increased catalase activities and glutathione levels in hepatocytes from chronically ethanol-fed rats.

Green tea protects against ethanol-induced lipid peroxidation in rat organs

Ethanol metabolism is accompanied by generation of free radicals, which stimulates lipid peroxidation. Natural antioxidants are particularly useful in such a situation. The current study was designed to investigate the efficacy of green tea, as a source of water-soluble antioxidants (catechins), on lipid peroxidation in liver, brain, and blood induced by chronic (4 weeks) ethanol intoxication in rats. Feeding of ethanol led to a significant increase in lipid peroxidation, as measured by increased concentrations of lipid hydroperoxides, 4-hydroxynonenal, and malondialdehyde. Feeding of ethanol also changed the glutathione-dependent lipid hydroperoxide decomposition system, resulting in a decrease in both reduced glutathione concentration and activity of glutathione peroxidase. Observed changes were statistically significant in all examined tissues. Enhancement in lipid peroxidation was associated with disruption of hepatocyte cell membranes, as observed through electron microscopic evaluation. Green tea protects phospholipids from enhanced peroxidation and prevents changes in biochemical parameters and morphologic changes observed after ethanol consumption. These results support the suggestion that green tea protects membranes from peroxidation of lipids associated with ethanol consumption.

Increase in 8-hydroxyguanine and its repair activity in the esophagi of rats given long-term ethanol and nutrition-deficient diet

Epidemiological studies have shown that an increased risk of esophageal cancer is associated with the chronic consumption of alcoholic beverages, although alcohol itself is not a carcinogen in animal models. Reactive oxygen species produced by the metabolism of ethanol or by chronic inflammation may play an important role in the carcinogenic process. In this study, we analyzed one type of oxidative DNA damage, 8-hydroxyguanine (8-OH-Gua), and its repair activity in the esophagus as indicators of cellular oxidative stress in rats given long-term ethanol and an autoclaved diet (nutrition-deficient diet). Three-week-old male Sprague-Dawley rats were fed an ethanol beverage whose concentration was increased from 12 to 70% over 20 weeks. When the concentration reached 50%, the diet of one group was changed from the regular diet to an autoclaved diet. At the feeding periods of 20, 25, 30, and 35 weeks, the rats were sacrificed and the 8-OH-Gua levels and repair activities within the esophagi were measured. After 30 weeks of ethanol- and autoclaved diet-feeding, significant increases of 8-OH-Gua and its repair activity were observed in the esophagi, but not in those of the ethanol- and normal diet-fed rats. This result indicates that the combined effects of long-term ethanol consumption and nutritional deficiency may be involved in inducing oxidative stress in the rat esophagus.

Dose response of ethanol on antioxidant defense system of liver, lung, and kidney in rat

This study investigated the alterations in levels of glutathione, lipid peroxidation, and antioxidant enzyme activity in the liver, lung, and kidney of rats treated with acute doses of ethanol. Male Fisher-344 rats were randomly divided into four groups, and were treated as follows: (1) vehicle (saline) control; (2) ethanol 2 g/kg, p.o.; (3) ethanol 4g/kg, p.o.; and (4) ethanol 6 g/kg, p.o. The animals were sacrificed 1 h after treatment, and tissues were isolated and analyzed. The hepatic GSH levels significantly decreased (73, 68, and 66% of control) due to ethanol ingestion at 2, 4, and 6g/kg, respectively. The hepatic GSH/GSSG ratio also decreased with increasing doses indicating stress response due to ethanol. The hepatic SOD activity significantly decreased (70, 75 and 71% of control) with graded doses of ethanol ingestion. The hepatic CAT/SOD and GSH-Px+CAT/SOD ratios significantly increased (147, 169 and 177% of control) and (140, 167 and 178% of control), respectively with increasing doses of ethanol. In the lung, graded doses of ethanol increased GSH-Px activity (120, 114 and 141% of control) and decreased GR activity (98, 89 and 89% of control), respectively. The MDA concentrations in the lung also increased after higher ethanol ingestion. Most of the antioxidant enzyme ratios increased with increasing doses of ethanol in the lung. In the kidney, GSH-Px activity increased (139, 119 and 151% of control), whereas GR activity decreased (84, 85 and 83% of control). GSH-Px/SOD and GSH-Px+CAT/SOD ratios increased whereas GR/GSH-Px ratio decreased after graded doses of ethanol. GSH levels in the kidney decreased after ethanol ingestion. MDA concentrations increased with increasing dose of ethanol in the kidney. These results showed the dose dependant and tissue specific changes in the antioxidant system after ethanol ingestion. Ethanol exerts oxidative stress on antioxidant systems of liver, lung and kidney in proportion to the amount of ethanol ingestion.

Interaction of 1-hydroxyethyl radical with antioxidant enzymes

There is considerable interest in the role of the 1-hydroxyethyl radical (HER) in the toxic effects of ethanol. The goal of this study was to evaluate the effects of HER on classical antioxidant enzymes. The interaction of acetaldehyde with hydroxylamine-o-sulfonic acid has been shown to produce 1, 1'-dihydroxyazoethane (DHAE); this compound appears to be highly unstable, and its decomposition leads to the generation of HER. Addition of DHAE into a solution of PBN led to the appearance of the typical EPR spectra of PBN/HER adduct. No PBN/HER spin adduct was detected when DHAE was incubated with 0.1 M PBN in the presence of GSH. In the absence of PBN, DHAE oxidized ascorbic acid to semidehydroascorbyl radical, presumably via an ascorbate-dependent one-electron reduction of HER back to ethanol. Catalase was progressively inactivated by exposure to DHAE-generated HER in a time and HER concentration-dependent manner. Ascorbic acid and PBN gave full protection to catalase against HER-dependent inactivation. The antioxidants 2-tert-butyl-4-methylphenol, propylgallate, and alpha-tocopherol-protected catalase against inactivation by 84, 88, and 39%, respectively. Other antioxidant enzymes were also sensitive to exposure to HER. Glutathione reductase, glutathione peroxidase, and superoxide dismutase were inactivated by 46, 36, and 39%, respectively, by HER. The results reported here plus previous results showing HER interacts with GSH, ascorbate, and alpha-tocopherol suggest that prolonged generation of HER in cells from animals chronically exposed to ethanol may lower the antioxidant defense status, thereby contributing to mechanisms by which ethanol produces a state of oxidative stress and produces toxicity.

Pathogenesis of alcoholic liver disease with particular emphasis on oxidative stress

Oxidative stress is well recognized to be 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 and/or by decreasing the level of endogenous antioxidants. Numerous experimental studies have emphasized the role of the ethanol-inducible cytochrome P450 in the microsomes and the molybdo-flavoenzyme xanthine oxidase in the cytosol. This review shows the putative role of ethanol-induced disturbances in iron metabolism in relation to iron as a pro-oxidant factor. Ethanol administration also affects the mitochondrial free radical generation. Many previous studies suggest a role for active oxygens in ethanol-induced mitochondrial dysfunction in hepatocytes. Recent studies in our laboratory in the Department of Internal Medicine, Keio University, using a confocal laser scanning microscopic system strongly suggest that active oxidants generated during ethanol metabolism produce mitochondrial membrane permeability transition in isolated and cultured hepatocytes. In addition, acetaldehyde, ethanol consumption-associated endotoxaemia and subsequent release of inflammatory mediators may cause hepatocyte injury via both oxyradical-dependent and -independent mechanisms. These cytotoxic processes may lead to lethal hepatocyte injury. Investigations further implicate the endogenous glutathione-glutathione peroxidase system and catalase as important antioxidants and cytoprotective machinery in the hepatocytes exposed to ethanol.

Free radicals and ethanol-induced cytotoxicity in neural crest cells

Associations between ethanol-induced cranial neural crest cell (NCC) damage in mammalian embryos and subsequent malformations as observed in human fetal alcohol syndrome have previously been illustrated. The vulnerability of NCCs to this teratogen may result, at least in part, from their sensitivity to free radical damage. To examine relationships between free radical generation and NCC cytotoxicity, primary culture of mouse NCCs was used. NCC viability was determined in both dose- and time-response studies involving ethanol exposure. After 48 hr of culture, cell viability was significantly diminished at all doses tested (i.e., 50, 100, 150, and 200 mM ethanol). At 100 mM ethanol (a dosage that is teratogenic in vivo and in whole embryo culture), cell viability decreased to approximately 50% of control values over the first 12 hr of culture, and decreased further, to approximately 20% by 48 hr. Using nitroblue tetrazolium as a probe, it was observed that exposure of NCCs to ethanol stimulated the production of superoxide anion radicals. Co-treatment of the ethanol-exposed NCCs with free radical scavengers including 300 units/ml of superoxide dismutase, catalase (500 units/ml), or alpha-tocopherol (300 microM) significantly improved NCC viability. These results suggest that the ethanol-induced NCC injury is mediated, at least in part, through the generation of free radicals. To test this hypothesis further, NCCs were exposed in culture to xanthine/xanthine oxidase. Exogenous free radicals generated by the xanthine/xanthine oxidase system resulted in reduced NCC viability, the severity of which increased in a time and enzyme concentration-related manner. Superoxide dismutase (300 units/ml) and catalase (500 units/ml) significantly reduced the effects of the xanthine/xanthine oxidase-generated free radicals on NCC viability. The similarity between the susceptibility of NCCs to ethanol and their susceptibility to exogenous free radicals in concert with the free radical scavenger-mediated amelioration of ethanol and exogenous free radical-induced NCC death strongly suggest that free radicals play a significant role in ethanol-induced NCC death.

Genetic regulation of gene-specific mRNA by ethanol in vivo and its possible role in ethanol preference in a cross with RI lines in mice

Relative ethanol preference is a well-recognized phenotype in a number of species, including mice, but the molecular basis for this phenotype remains speculative. We generated novel recombinant inbred (RI) mouse lines from C57BL/6J (ethanol preferring) and BALB/c (ethanol avoiding) strains and evaluated the effect of ethanol feeding on the mRNA levels of three genes (Adh-1, Ahd-2, and Cas-1) of alcohol metabolism. Ethanol feeding affects the mRNA levels of all three genes in both a gene- and a genotype-specific manner. The effect of ethanol feeding on Ahd-2 mRNA, in particular, is highly correlated with the relative ethanol acceptance of the genotypes. DNA sequencing of approximately 500 bp of the 5' upstream region of the Ahd-2 gene has yielded identical sequence for the two strains and the genetically determined associated factors are hypothesized to be regulatory proteins. Quantitative trait locus analysis on the RI lines should lead to the molecular characterization and mapping of such gene-specific regulatory factors.

Teratogenic effects of ethanol in the Quackenbush special mouse

The intragastric exposure of QS mice to alcohol both under short-term (6-day period) (3.0 g/kg, but not 1.5 g/kg, body weight/day through gestation day (GD) 7 to GD 12) and long-term (chronic) (15% ethanol in drinking water beginning several weeks before mating and continuing into pregnancy) conditions reduced the weight, size, and protein content of GD 12 embryos, and the weight of GD 18 embryos. The incidence of brachydactyly with delayed ossification was also significantly greater in embryos chronically exposed to alcohol than in controls (45% vs. 6.7%). The short-term and long-term exposure regimens produced incidences of only 1% and 5.8%, respectively, of forelimb ectrodactyly in GD 18 embryos. It was concluded that alcohol exerts embryo growth retarding effects in pregnant QS mice without inducing a high incidence of skeletal defects. Thus, the QS mouse could serve as an excellent model to resolve the mechanisms whereby alcohol induces pre- and post-natal growth restrictions during pregnancy.

Ethanol-induced oxidative stress in the liver

Oxygen stress is well recognized to be 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 and/or by decreasing the level of endogenous antioxidants. Numerous experimental studies have emphasized the role of the ethanol-inducible cytochrome P-450 in the microsomes, as well as the molybdo-flavoenzymes xanthine oxidase in the cytosol. This review shows the putative role of ethanol-induced disturbances in iron metabolism in relation to iron as a prooxidant factor. Ethanol administration also affects the mitochondrial free radical generation. Although many previous studies suggest a role for active oxygens in ethanol-induced mitochondrial dysfunction in hepatocytes, the detailed mechanism of ethanol-induced oxidative stress on mitochondria remains to be clarified further. Studies of our laboratory using a confocal laser scanning microscopic system strongly suggest that active oxidants produced during ethanol metabolism modulate mitochondrial energy synthesis in isolated and cultured hepatocytes. In addition, our investigations implicate endogenous glutathione-glutathione peroxidase system and catalase as important antioxidants and cytoprotective machinery in the hepatocyte mitochondria exposed to ethanol. The fluorographic investigations using the confocal laser scanning microscopy may be useful to extend our knowledge and provide a new view about ethanol-associated oxidative stress and metabolic changes in hepatocytes.

Oxidative stress and the fetotoxicity of alcohol consumption during pregnancy

Pregnant Quackenbush Special mice were exposed to ethanol under semiacute (3.0 g/kg body weight intragastrically, days 7 to 12 of pregnancy), and chronic conditions (15% ethanol in drinking water for 5 weeks before and during pregnancy) to assess whether embryo-fetotoxic actions of the drug involve oxidative stress effects. Effects were monitored both in the maternal system and embryo. Alcohol compromised the maternal system by increasing the generation of lipid peroxides in the liver. It also decreased glutathione and vitamin E levels, and glutathione peroxidase and superoxide dismutase activities in this organ. Glutathione peroxidase activity in the maternal blood decreased. Only minor alcohol-induced changes occurred in the uterine endometrium, including decreased xanthine oxidase and increased gamma-glutamyl transpeptidase. Similarly, only few changes were induced in day-12 embryos by alcohol. In this case, glutathione content and xanthine oxidase activity decreased while glutathione reductase activity increased following exposure to the chronic regime. With the possible exception of the maternal liver where evidence of oxidative damage was detected, these results do not reflect substantial changes in the antioxidant defences of either the pregnant mouse or embryo. However, the changes may contribute to the growth retarding and other fetotoxic effects of alcohol when they are totalled into the multifactorial actions of the drug.

Liver antioxidant defenses in mice fed ethanol and the AIN-76A diet

The effects of chronic alcohol (EtOH) ingestion on antioxidant defenses in mice fed AIN-76A liquid diets were investigated. C57Bl/6 female mice were divided into three groups and fed the AIN-76A liquid EtOH diet containing EtOH to provide 31% of total caloric intake (TCI), the same basic diet containing EtOH to provide 35% of TCI, or an isocaloric AIN-76A liquid control diet. After 3 weeks, the mice were killed and livers were excised for biochemical analysis. Liver reduced glutathione (GSH) levels, and activities of both Mn-superoxide dismutase (SOD) and Cu/Zn-SOD were significantly decreased by both levels of EtOH. Activities of catalase and glutathione transferase (GT) were significantly increased, whereas glutathione peroxidase (GP) activity was not affected by either level of EtOH. Our previous study using the Lieber-DeCarli liquid EtOH diet caused a decline of total SOD and GP activities. The results suggest that chronic EtOH administration decreases liver antioxidant defenses; however, the mice fed the AIN-76A EtOH liquid diet can maintain a higher antioxidant defense capability than those fed Lieber-DeCarli EtOH liquid diet.

Prooxidant and antioxidant hepatic factors in rats chronically fed an ethanol regimen and treated with an acute dose of lindane

While acute lindane treatment and chronic ethanol feeding to rats have been associated with hepatic oxidative stress, the possible roles of these stresses in the pathogenesis of hepatic lesions reported in acute lindane intoxication and in those observed in some models of chronic alcoholism have not been established. Our previous studies in rats chronically fed ethanol regimens and then treated with a single intraperitoneal (i.p.) dose of lindane (20 mg/kg) showed that while lindane per se was invariably associated with hepatic oxidative stress, chronic ethanol feeding only produced this stress when the dietary level of vitamin E was relatively low. Chronic ethanol pretreatment did not significantly affect the lindane-associated oxidative stress, and neither chronic ethanol feeding nor acute lindane, single or in combination, produced any histologic and biochemical evidence of liver damage. In the present experiment, the acute dose of lindane was increased to 40 mg/kg, and we have studied a larger number of prooxidant and antioxidant hepatic factors. Male Wistar rats (115.5 +/- 5.4 g) were fed ad lib for 11 weeks a calorically well-balanced and nutritionally adequate basal diet, or the same basal diet plus a 32% ethanol/25% sucrose solution, also ad lib, and were then injected i.p. with a single dose of lindane or with equivalent amounts of corn oil. The results indicated that acute lindane treatment to naive rats increased practically all the prooxidant hepatic factors examined (cytochromes P450 and b5, NADPH cytochrome c reductase, NADPH oxidase), as well as the generation of microsomal superoxide radical and thiobarbituric acid reactive substances of liver homogenates, but did not modify any of the antioxidant hepatic factors studied. Conversely, the chronic administration of ethanol alone did not significantly affect the prooxidant hepatic factors but reduced some of the antioxidants (i.e., the activities of GSH-Px and the contents of alpha-tocopherol and ubiquinols 9 and 10). Although chronic ethanol pretreatment further increased the superoxide generation induced by lindane per se, it did not increase but generally reduced the effects of lindane per se on the other prooxidant factors studied. Furthermore, although acute lindane administration to ethanol-pretreated rats was associated with decreases in GSH and catalase (not affected by ethanol or lindane treatment alone), it did not substantially modify the reducing effects of ethanol feeding per se on GSH-Px, alpha-tocopherol, and ubiquinols. Once again, neither chronic ethanol feeding nor lindane treatment, single or in combination, was associated with any evidence of liver damage.

Inactivation of Cu,Zn-superoxide dismutase by free radicals derived from ethanol metabolism: a gamma radiolysis study

The reactions of free radicals derived from ethanol metabolism with Cu,Zn SOD were studied. 1-Hydroxyethyl radicals were generated by gamma radiolysis of a N2O-saturated ethanolic solution (10(-2) M) in phosphate buffer (10(-3) M, pH 7.4). To generate acetyl radicals by gamma radiolysis, we used ethylene glycol (10(-2) M) in phosphate buffer (10(-3) M, pH 7.4). This allows us to avoid the use of acetaldehyde, which may be toxic toward various cellular constituents. We have previously reported that HO. radicals reacting with either acetaldehyde or ethylene glycol produce the same free radicals (Santiard et al., 1991, J. Chim. Phys. 88, 967-976). the rate constant reaction of 1-hydroxyethyl free radicals with Cu,Zn-SOD was measured separately by competition kinetics with the spin trapping agent alpha-(4-pyridyl 1-oxide) N-terbutylnitrone (4-POBN), after having measured the rate constant of scavenging of 1-hydroxyethyl free radicals by 4-POBN in the absence of SOD. We found k1 (4-POBN + 1-hydroxyethyl radical) = 4.2 10(5) M-1 s-1 and kR (SOD + 1-hydroxyethyl radical) = 6.8 10(5) M-1 s-1). 1-Hydroxyethyl or acetyl radicals produced dose-dependent Cu,Zn-SOD inactivation. The inactivation rate constant of Cu,Zn-SOD by 1-hydroxyethyl radicals is ki = 1.13 10(4) M-1 s-1. Free radicals derived from ethanol metabolism can thus react SOD leading to enzyme inactivation, besides the fact that the reactivities of 1-hydroxyethyl radicals with 4-POBN and with proteins such as Cu,Zn SOD are of the same order of magnitude could explain the difficulties to trap in vivo these radicals.

Antioxidant defense mechanisms in the female rat: interactions with alcohol, copper, and type of dietary carbohydrate

The purpose of this study was to examine the effects of ethanol, type of dietary carbohydrate (fructose vs. starch), and levels of dietary copper (deficient vs. adequate) on antioxidant defense mechanism in the female rat. The consumption of 20% ethanol in the drinking water depressed growth rate due to a reduction of feed efficiency. Ethanol also lowered hepatic copper concentration, but had no effect on hepatic iron. Among the three antioxidant enzymes studied [i.e., superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase], only catalase activity was increased by ethanol. This effect was independent of copper or the type of dietary carbohydrate. As expected, copper deficiency dramatically reduced SOD. Copper deficiency also reduced GSH-Px activity; however, the combination of fructose feeding with copper deficiency caused a further reduction in GSH-Px. The data show that copper deficiency, per se, and the combination of copper deficiency with fructose feeding lower the antioxidant defense system in female rats.

Blood and liver lipid peroxide status after chronic ethanol administration in rats

During the last decades a vast number of reports have aimed at elucidating the mechanisms behind alcohol-related organ injury, but the manner in which ethanol induces, e.g., liver damage is still an enigma. Increased oxidative stress has been put forward as one possible mechanism behind alcohol-related tissue damage. This paper focuses on the effect of chronic ethanol consumption on antioxidant status and lipid peroxide levels in blood and liver of rats. Alcohol was given twice daily in a total dose of 5 g ethanol/kg body wt. per day divided into two 2.5 g ethanol/kg body wt. doses as a 50% water solution, by gavage over 4 weeks. Chronic ethanol ingestion led neither to a significant change in lipid peroxide formation nor to a significant change in enzymatic antioxidant activities. Only concentrations of oxidized glutathione and of other non-enzymatic antioxidant such as vitamin E showed a tendency to decrease after alcohol application. The data presented could serve to emphasize no involvement of free radical-induced lipoperoxidation in the pathogenesis of ethanolic liver diseases.

Effects of chronic alcohol feeding and murine AIDS virus infection on liver antioxidant defense systems in mice

Whether ethanol (ETOH) abuse could contribute to the development of acquired immunodeficiency syndrome (AIDS) among human immunodeficiency virus (HIV)-positive drug abusers is a critical question for which little experimental information is available. This study was designed to determine if chronic ETOH feeding and murine AIDS virus infection cooperatively affected liver antioxidant defense systems in C57B1/6 female mice. Mice were divided into two groups and fed the Lieber-DeCarli liquid ETOH diet containing ETOH at a concentration to provide 31% of total caloric intake or an isocaloric liquid control (control) diet in which dextrin-maltose replaced ETOH. One week after the initiation of ETOH feeding, half of the mice in each diet group (8 mice) were injected intraperitoneally with murine retrovirus (MAIDS) stock. After 3 and 5 weeks of ETOH feeding, half of the mice in each of the four treatment groups (4 mice) were killed, and livers were excised for biochemical analysis. Liver reduced glutathione (GSH) levels and activities of glutathione peroxidase (GP), glutathione reductase (GR), glutathione transferase (GT), catalase and superoxide dismutase (SOD), and serum ETOH concentrations were determined. The results demonstrated that serum ETOH concentrations were significantly elevated in ETOH-MAIDS group when compared with the ETOH group. Moreover, chronic ETOH feeding and MAIDS infection independently depressed liver antioxidant defense capability, and together led to an additive inhibition of GSH and SOD activities. In addition, MAIDS infection inhibited an ETOH-induced increase in catalase and GT activities. These results suggest that alcohol abuse could contribute to the development of AIDS by inhibiting the protective capability of an infected individual against oxidative stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Ethanol-induced oxidative stress and nutritional status

The ability of dietary ethanol, administered over a 10-day period, to elevate production rates of reactive oxygen species and to alter glutathione levels has been determined in both liver and cerebellum, a brain region known to be susceptible to ethanol-induced damage. Two groups of ethanol-consuming rats were used. One set of treated animals that received an all-liquid ethanol-containing diet experienced weight gain, and this gain was matched in a pair-fed control group. The other ethanol-treated group that had free access only to solid chow and water containing ethanol lost weight during the exposure period. The corresponding control group that received unlimited water and chow was allowed to gain weight normally. In animals that lost weight as a consequence of ethanol in the drinking water, evidence of oxidative stress was enhanced relative to that in animals receiving ethanol by way of the liquid diet. This latter set gained weight, despite higher blood ethanol levels than the group that lost weight. An excess prooxidant condition prevailed in the liver and cerebellum of the ethanol-dosed malnourished group. In the case of liver, this difference may relate to a greater lability of iron-containing proteins in the rats that experienced weight loss, leading to the appearance of low molecular weight iron in the cytosol.

Ethanol toxicity and oxidative stress

The mechanisms underlying the toxicity of ethanol have been the subject of much study, but are not well understood. Unlike many selective pharmacological agents, ethanol clearly has several major loci of action. One deleterious factor in ethanol metabolism is the potential for generation of excess amounts of free radicals. The extent to which this activity accounts for the overall toxicity of ethanol is unknown. This review outlines the enzymic steps that have the capacity to generate reactive oxygen species. These steps are likely to differ in acute and extended exposures to ethanol. Acetaldehyde catabolism also has the likelihood of contributing to ethanol-related oxidative stress. The review focuses on the ethanol-induced production of excess amounts of pro-oxidant reactive species in both the liver and the central nervous system. The potential of various stages of ethanol catabolism to involve generation of free radicals is described.

Effects of chronic ethanol administration on free radical defence in rat myocardium

Cellular protection against free radical reactions was measured in myocardium from ethanol-fed rats using ethanol administration in drinking water as a model of moderate alcohol intoxication. The activities of Cu,Zn-superoxide dismutase (SOD) and glutathione-S-transferase were higher in ethanol-fed rats than in controls, whereas Mn-SOD, catalase and glutathione peroxidase activities were not altered by ethanol treatment. Myocardial zinc was higher and selenium concentration lower in ethanol-fed rats than in controls. Ethanol consumption, which failed to modify the myocardial vitamin E level, did not result in increased lipid peroxidation, but decreased cytosolic and membraneous protein thiols.

Implication of free radical mechanisms in ethanol-induced cellular injury

Numerous experimental data reviewed in the present article indicate that free radical mechanisms contribute to ethanol-induced liver injury. Increased generation of oxygen- and ethanol-derived free radicals has been observed at the microsomal level, especially through the intervention of the ethanol-inducible cytochrome P450 isoform (CYP2E1). Furthermore, an ethanol-linked enhancement in free radical generation can occur through the cytosolic xanthine and/or aldehyde oxidases, as well as through the mitochondrial respiratory chain. Ethanol administration also elicits hepatic disturbances in the availability of non-safely-sequestered iron derivatives and in the antioxidant defense. The resulting oxidative stress leads, in some experimental conditions, to enhanced lipid peroxidation and can also affect other important cellular components, such as proteins or DNA. The reported production of a chemoattractant for human neutrophils may be of special importance in the pathogenesis of alcoholic hepatitis. Free radical mechanisms also appear to be implicated in the toxicity of ethanol on various extrahepatic tissues. Most of the experimental data available concern the gastric mucosa, the central nervous system, the heart, and the testes. Clinical studies have not yet demonstrated the role of free radical mechanisms in the pathogenesis of ethanol-induced cellular injury in alcoholics. However, many data support the involvement of such mechanisms and suggest that dietary and/or pharmacological agents able to prevent an ethanol-induced oxidative stress may reduce the incidence of ethanol toxicity in humans.

Influence of copper status on the response to acute ethanol exposure in rats

An acute dose of ethanol was used to investigate the biochemical response of tissues with a compromised antioxidant defense system to a surge of oxygen radical production. The copper (Cu)-deficient rat served as the animal model for this study based on its compromised antioxidant defense system. Rats were fed control (10 micrograms Cu/g) or Cu-deficient (0.2 microgram Cu/g) diet for 14 days. In order to minimize secondary effects associated with chronic Cu deficiency, the chelator triethylenetetramine was added to the Cu-deficient diet to shorten the time required for the induction of Cu deficiency. On day 14, rats were gavaged with ethanol (4.5 g/kg b.wt.) or saline and killed 9 hours postgavage. Rats fed the Cu-deficient diets had lower liver superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities than controls. Ethanol treatment had no effect on liver CuZnSOD or Gpx activity, while MnSOD activity was higher than saline control levels following EtOH treatment. Despite low GPx and SOD activity, Cu-deficient rats did not exhibit higher hepatic thiobarbituric acid reacting substances (TBARS) than controls; in fact, hepatic microsomal TBARS were lower in saline-treated Cu-deficient rats relative to Cu-sufficient rats. Ethanol treatment resulted in higher whole homogenate and mitochondrial TBARS than in saline-gavaged rats. Copper status did not influence hepatic TBARS production in response to an acute EtOH load. These data suggest that compensatory mechanisms contribute to the protection of the liver from excessive free radical production in this model of Cu deficiency.

Nickel-induced renal lipid peroxidation in different strains of mice: concurrence with nickel effect on antioxidant defense systems

Lipid peroxidation (LPO) and active oxygen-detoxifying enzymes, catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), as well as glutathione (GSH) and some related enzymes, glutathione-S-transferase (GST) and glutathione reductase (GSSG-R) were assayed in kidneys of BALB/cAnNCr (BALB/c), C3H/HeNCr-MTV- (C3H), B6C3F1, and C57BL/6NCr (C57BL) mice 3-48 h after a single intraperitoneal injection of 170 mumol nickel (II) acetate (NiAcet)/kg body wt. In control mice that received 340 mumol sodium acetate/kg, the levels of enzymes and GSH did not significantly vary in time but were different in various strains. The basal activities of CAT and SOD in in the controls were highest in BALB/c and lowest in C57BL mice (1.8:1.0 and 1.4:1.0 respectively) in contrast to that of GSH-Px which was highest in B6CF1 and lowest in BALB/c (1.3:1.0; P less than 0.05). The strain ranking of control concentrations of renal GSH was B6C3F1 greater than C3H greater than or equal to C57BL greater than BALB/c (2.8:2.4:2.3:1.0), and that of GSSG-R was C3H greater than or equal to BALB/c greater than B6C3F1 greater than or equal to C57BL [corrected] (1.5:1.4:1.1:1.0). The basal activity of renal GST in control mice was 25% lower in C3H than in any of the other 3 strains. The renal LPO levels in the control mice did not vary among strains. Nickel treatment transiently increased renal LPO levels in the control mice did not vary among strains. Nickel treatment transiently increased renal LPO in the BALB/c mice by 100%, in B6C3F1 by 30%, and in C57BL by 20% (P less than 0.05), with no significant effect in C3H mice. Thus, the magnitude of nickel-induced renal LPO was greatest in the strain that is lowest in GSH and GSH-Px, but not in CAT and SOD. Nickel effects on GSH and the enzymes were time-dependent and included transient inhibition or enhancement of different proportions with no apparent strain- and/or base level-related patterns, or concurrence with LPO. The results emphasize the importance of GSH and GSH-Px for preventing nickel-induced oxidative cell damage.

The decrease of superoxide dismutase activity and depletion of sulfhydryl compounds in ethanol-induced liver injury

There appears to be increasing evidence that ethanol toxicity may be associated with an increased production of reactive oxygen intermediates. In rats we studied the effect of 4 weeks of ethanol ingestion on the liver cytosolic defense system against active oxygen species. Compared with the control rats, the ethanol-fed animals had a significantly higher liver malondialdehyde content and significantly lower reduced glutathione level. Moreover, ethanol feeding resulted in a decrease of superoxide dismutase and catalase activities while glutathione peroxidase activity was only slightly diminished. Thus, prolonged ethanol administration profoundly modified the hepatic status of the enzymatic defense system leading to lipid peroxidation that may disrupt vital functions of liver cells.

Nickel-induced lipid peroxidation in the liver of different strains of mice and its relation to nickel effects on antioxidant systems

After a single intraperitoneal injection of 170 mumol nickel(II)acetate/kg body wt., the activity of hepatic catalase (CAT) decreased by 25-56% in a strain- and time-dependent manner, the most susceptible being C57BL/6NCr greater than C3H/HeNCr-MTV- greater than B6C3F1 greater than or equal to BALB/cAnNCr mice. The glutathione (GSH) levels in all 4 strains were inhibited by nickel with the C57BL/6NCr mice showing the biggest decrease (68%) followed by BALB/cAnNCr (46%) greater than or equal to B6C3F1 (42%) greater than C3H/HeNCr-MTV- (22%). The response of hepatic glutathione peroxidase (GSH-Px) to nickel was variable and included 30% enhancement in C3H/HeNCr-MTV- or lack of biologically significant effect (max. +/- 10% variations in time) in the remaining strains. The activity of glutathione reductase (GSSG-R) increased gradually by up to 30% (48 h post-injection) in B6C3F1 and C3H/HeNCr-MTV- mice or, transiently, by 15-18% (3 h), in C57BL/6NCr and BALB/cAnNCr mice. Also, in some strains, nickel significantly affected superoxide dismutase (SOD) (14-19% loss in C57BL/6NCr and B6C3F1 mice, respectively), and GSH-S-transferase (GST) (26% loss in C3H/HeNCr-MTV- mice). Lipid peroxidation (LPO) in the liver reached its highest value 24 h after nickel treatment in C57BL/6NCr (549% over the control) greater than or equal to BALB/cAnNCr (519%) greater than B6C3F1 (426%) much greater than C3H/HeNCr-MTV- (39%). In conclusion, the magnitude of nickel-induced LPO shows a reverse correlation with the extent and direction of nickel effect on GSH, GSH-Px and GSSG-R, but not on CAT, SOD or GST.

A quantitative genetic analysis of tissue-specific catalase activity in Mus musculus

Tissue-specific catalase activity in 3-week-old animals from inbred mouse strains 129/ReJ, BALB/c, C3H/HeAnl/Cas-1b, C3H/HeSnJ, C3H/S, C57BL/6J, and Swiss-Webster was found to be highly variable by analysis of variance (P = 0.01). Appropriate crosses were made among strains which were classified as normal (BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (129/ReJ, C57BL/6J), and acatalasemic (C3H/HeAnl/Cas-1b) with respect to blood catalase activity to study the inheritance of the blood, kidney, liver, and lung catalase activity levels in a number of generations (reciprocal F1's, F2, two backcrosses--BC1 and BC2--and some RI lines). Segregation analysis and statistical methods which tested different models of inheritance as well as calculations of heritability were used in an effort to assess and evaluate genetic parameters that affect catalase activity. Results indicate that the inheritance of blood catalase activity in the cross involving acatalasemic and normal (BALB/c, C3H/HeSnJ) strains is compatible with the single-locus difference between the parental strains; however, the difference between the acatalasemic and the hypocatalasemic strain (C57BL/6J) would require additional genetic interaction for a satisfactory explanation. A similar pattern of generalization also applies to the inheritance of kidney catalase activity. The segregation pattern for the liver and lung catalase activity in most crosses is significantly different from the expectations of the single locus model. These results are compatible with the concept that a number of genes must affect tissue-specific catalase activity in mice. These may include previously described (e.g., Ce-1 and Ce-2) or novel genetic regulators/modifiers which interact with a single structural gene (Cas-1) or its product to produce the catalase phenotype characteristic of specific tissues in each strain.

Antioxidant protection systems of rat lung after chronic ethanol inhalation

The effect of chronic ethanol administration on pulmonary antioxidant protection systems was investigated in male Sprague-Dawley rats exposed to room air or room air containing ethanol vapors for 5 weeks. Blood ethanol concentrations in ethanol-exposed rats were usually between 200 and 300 mg/dl. Glutathione, vitamin E, and malondialdehyde concentrations were measured in lung homogenates, and antioxidant enzyme activities (catalase, glutathione peroxidase, Cu/Zn-superoxide dismutase, glutathione reductase) were determined in the supernatant fractions. For comparison, the measurements were also made using liver fractions. Ethanol treatment increased the activities of catalase (117%) and Cu/Zn-superoxide dismutase (25%) in lung but not in liver. Although chronic ethanol inhalation lowered hepatic glutathione (19%) and hepatic vitamin E (33%), there was no increase in malondialdehyde content in either liver or lung of ethanol-exposed rats. The elevation of pulmonary antioxidant enzyme activities could be interpreted to mean that lung is a target for ethanol-induced oxidative stress. However, as there was no loss of pulmonary GSH or vitamin E and no increase in malondialdehyde formation, it appears that long-term ethanol exposure did not produce a significant degree of oxidative stress in rat lung.

Chemotactic activity for human PMN generated during ethanol metabolism by rat hepatocytes: role of glutathione and glutathione peroxidase

Infiltration of the liver by polymorphonuclear leukocytes is a characteristic feature of alcoholic hepatitis. We have previously shown that liver cytosol metabolizing ethanol generates chemoattractant activity for polymorphonuclear leukocytes and that hydroxyl radical scavengers inhibit this process. To investigate the possibility that endogenous glutathione and glutathione peroxidase also inhibit this process, we evaluated chemoattractant activity production by glutathione and glutathione peroxidase deficient rat liver cytosol during ethanol metabolism. Incubation of cytosol deficient in both glutathione and glutathione peroxidase with 10 mM ethanol for 1 hour resulted in a 500-fold increase in chemoattractant activity when compared to cytosol with normal glutathione and glutathione peroxidase content. These findings provide further evidence for a role of oxygen free radicals in the generation of chemotactic activity and they also suggest that the ethanol-induced decrease in hepatic glutathione and glutathione peroxidase reported by others may have a significant potentiating effect on the recruitment of pro-inflammatory cells into the liver.