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

Binge alcohol induces NRF2-related antioxidant response in the skeletal muscle of female mice

BACKGROUND

Chronic alcohol enhances oxidative stress, but the temporal response of antioxidant genes in skeletal muscle following a binge drinking episode remains unknown.

METHODS

Experiment 1: C57BL/6Hsd female mice received an IP injection of saline (CON; n = 39) or ethanol (ETOH; n = 39) (5 g/kg). Gastrocnemius muscles were collected from baseline (untreated; n = 3), CON (n = 3), and ETOH (n = 3) mice every 4 h for 48 h. Experiment 2: Gastrocnemius muscles were collected from control-fed (CON-FED; n = 17), control-fasted (CON-FAST; n = 18), or alcohol-fed (ETOH-FED; n = 18) mice every 4hrs for 20hrs after saline or ethanol (5 g/kg).

RESULTS

EtOH enhanced Superoxide dismutase 1 (Sod1) and NADPH Oxidase 4 (Nox4) from 24 to 48hr after the binge, while Sod2 and Nox2 were suppressed. Nuclear factor erythroid-derived 2-like 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) increased 12hrs after intoxication. Cytochrome P450 oxidoreductase (Por), Heme oxygenase 1 (Ho1), Peroxiredoxin 6 (Prdx6), Glutamate-cysteine ligase catalytic subunit (Gclc), Glutamate-cysteine ligase modifier subunit (Gclm), and Glutathione-disulfide reductase (Gsr) were increased by ETOH starting 12-16hrs post-binge. Fasting had similar effects on Nrf2 compared to alcohol, but downstream targets of NRF2, including Por, Ho1, Gclc, and Gclm, were differentially altered with fasting and EtOH.

CONCLUSION

These data suggest that acute alcohol intoxication induced markers of oxidative stress and antioxidant signaling through the NRF2 pathway and that there were effects of alcohol independent of a possible decrease in food intake caused by binge intoxication.

The Status of Oxidative Stress in Patients with Alcohol Dependence: A Meta-Analysis

Alcohol-induced oxidative stress (OS) plays a pivotal role in the pathophysiology of alcohol dependence (AD). This meta-analysis was aimed at investigating the changes in the levels of OS biomarkers in AD patients. We included relevant literature published before 1 April 2022, from the PubMed, Web of Science, and EBSCO databases following PRISMA guidelines. Finally, 15 eligible articles were enrolled in this meta-analysis, including 860 patients and 849 controls. Compared with healthy controls, AD patients had lower activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymes, and lower levels of albumin, while levels of malondialdehyde (MDA), vitamin B12, homocysteine, and bilirubin were significantly increased in serum/plasma samples of AD subjects (all p < 0.05). In male patients, the activities of SOD and GPx were increased in serum/plasma but decreased in erythrocytes (all p < 0.05). The opposite trends in the level of SOD and GPx activities in serum/plasma and erythrocytes of male patients could be used as the biomarker of alcohol-induced OS injury, and the synergistic changes of MDA, vitamin B12, albumin, bilirubin, and homocysteine levels should also be considered.

The evolution of radiobiology through the work of women scientists: the work of Christiane Ferradini

PURPOSE

Pay tribute to Christiane Ferradini and highlight the importance of her work as a scientist.

CONCLUSIONS

Christiane Ferradini was born in 1924 in the south of France. She graduated from the Paul Sabatier University in Toulouse, France. In 1947, she joined the Curie Laboratory of the Radium Institute (which was then under the leadership of Madame Irène Joliot-Curie) to pursue her doctoral research. After her defence in 1955, she commenced her journey dedicated to the advancement of science. She became an exceptional teacher. She led a research group that contributed, through many fruitful collaborations, to the opening of a new chapter in radiation biology and medicine. Together they shed light on free radical formation and their reactions with biomolecules. Christiane published a total of 190 scientific articles and 9 books. She died in 2002.

A hot water extract of turmeric (Curcuma longa) suppresses acute ethanol-induced liver injury in mice by inhibiting hepatic oxidative stress and inflammatory cytokine production

Turmeric (Curcuma longa) is a widely used spice that has various biological effects, and aqueous extracts of turmeric exhibit potent antioxidant activity and anti-inflammatory activity. Bisacurone, a component of turmeric extract, is known to have similar effects. Oxidative stress and inflammatory cytokines play an important role in ethanol-induced liver injury. This study was performed to evaluate the influence of a hot water extract of C. longa (WEC) or bisacurone on acute ethanol-induced liver injury. C57BL/6 mice were orally administered WEC (20 mg/kg body weight; BW) or bisacurone (60 µg/kg BW) at 30 min before a single dose of ethanol was given by oral administration (3·0 g/kg BW). Plasma levels of aspartate aminotransferase and alanine aminotransferase were markedly increased in ethanol-treated mice, while the increase of these enzymes was significantly suppressed by prior administration of WEC. The increase of alanine aminotransferase was also significantly suppressed by pretreatment with bisacurone. Compared with control mice, animals given WEC had higher hepatic tissue levels of superoxide dismutase and glutathione, as well as lower hepatic tissue levels of thiobarbituric acid-reactive substances, TNF-α protein and IL-6 mRNA. These results suggest that oral administration of WEC may have a protective effect against ethanol-induced liver injury by suppressing hepatic oxidation and inflammation, at least partly through the effects of bisacurone.

Antioxidant properties of glutamine and its role in VEGF-Akt pathways in portal hypertension gastropathy

AIM

To investigate the effects of glutamine on oxidative/nitrosative stress and the vascular endothelial growth factor (VEGF)-Akt-endothelial nitric oxide synthase (eNOS) signaling pathway in an experimental model of portal hypertension induced by partial portal vein ligation (PPVL).

METHODS

Portal hypertension was induced by PPVL. The PPVL model consists of a partial obstruction of the portal vein, performed using a 20 G blunt needle as a guide, which is gently removed after the procedure. PPVL model was performed for 14 d beginning treatment with glutamine on the seventh day. On the fifteenth day, the mesenteric vein pressure was checked and the stomach was removed to test immunoreactivity and oxidative stress markers. We evaluated the expression and the immunoreactivity of proteins involved in the VEGF-Akt-eNOS pathway by Western blotting and immunohistochemical analysis. Oxidative stress was measured by quantification of the cytosolic concentration of thiobarbituric acid reactive substances (TBARS) as well as the levels of total glutathione (GSH), superoxide dismutase (SOD) activity, nitric oxide (NO) production and nitrotyrosine immunoreactivity.

RESULTS

All data are presented as the mean ± SE. The production of TBARS and NO was significantly increased in PPVL animals. A reduction of SOD activity was detected in PPVL + G group. In the immunohistochemical analyses of nitrotyrosine, Akt and eNOS, the PPVL group exhibited significant increases, whereas decreases were observed in the PPVL + G group, but no difference in VEGF was detected between these groups. Western blotting analysis detected increased expression of phosphatidylinositol-3-kinase (PI3K), P-Akt and eNOS in the PPVL group compared with the PPVL + G group, which was not observed for the expression of VEGF when comparing these groups. Glutamine administration markedly alleviated oxidative/nitrosative stress, normalized SOD activity, increased levels of total GSH and blocked NO overproduction as well as the formation of peroxynitrite.

CONCLUSION

Glutamine treatment demonstrated to reduce oxidative damage but does not reduce angiogenesis induced by PH in gastric tissue, demonstrating a beneficial role for the PI3K-Akt-eNOS pathway.

Modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration

Excessive consumption of fluoride and ethanol has been identified as injurious to human health. Fluoride and ethanol co-exposures are commonly seen among the alcoholics residing in endemic fluoride areas worldwide. This study was undertaken to examine the modulation of lipid peroxidation and antioxidant defense systems in rat intestine by subchronic fluoride and ethanol administration. Female Sprague-Dawley rats were divided into four groups: group I (control), group II (fluoride was given orally at a dose of 25 mg/kg body weight), group III (30% ethanol was given orally at a dose of 1 mL/kg body weight), and group IV (a combination of fluoride and ethanol was administered orally at the dose described for groups II and III). Lipid peroxidation was elevated (P<.05) in intestine of rats by fluoride or ethanol treatments for 20 or 40 days. However, glutathione content was reduced by fluoride (32 and 44%) and ethanol (21 and 40%) treatments after 20 and 40 days, respectively. Fluoride-exposed animals showed reduction (P<.05) in the activities of superoxide dismutase (22 and 42%), catalase (30 and 37%), glutathione peroxidase (22 and 35%), glutathione reductase (32 and 34%), and glutathione-S-transferase (24 and 30%) after 20 and 40 days. A similar decrease (P<.05) in the activities of these enzymes was also noticed in animals exposed to ethanol for 20 or 40 days. The observed changes in lipid peroxidation, reduced glutathione levels, and enzyme systems were further augmented in intestine of rats exposed to fluoride and ethanol together. Intestinal histology showed large reactive lymphoid follicles along with mild excess of lymphocytes in lamina propria of villi, villous edema, focal ileitis, and necrosis of villi in animals exposed to fluoride and ethanol for 40 days. These findings suggest that fluoride and ethanol exposure induces considerable changes in lipid peroxidation, antioxidant defense, and morphology of rat intestine, which may affect its functions.

Hepatoprotective effects of pecan nut shells on ethanol-induced liver damage

The hepatoprotective activity of the aqueous extract of the shells of pecan nut was investigated against ethanol-induced liver damage. This by-product of the food industry is popularly used to treat toxicological diseases. We evaluated the phytochemical properties of pecan shell aqueous extract (AE) and its in vitro and ex vivo antioxidant activity. The AE was found to have a high content of total polyphenols (192.4±1.9 mg GAE/g), condensed tannins (58.4±2.2 mg CE/g), and antioxidant capacity, and it inhibited Fe(2+)-induced lipid peroxidation (LP) in vitro. Rats chronically treated with ethanol (Et) had increased plasmatic transaminases (ALT, AST) and gamma glutamyl transpeptidase (GGT) levels (96%, 59.13% and 465.9%, respectively), which were effectively prevented (87; 41 and 383%) by the extract (1:40, w/v). In liver, ethanol consumption increased the LP (121%) and decreased such antioxidant defenses as glutathione (GSH) (33%) and superoxide dismutase (SOD) (47%) levels, causing genotoxicity in erythrocytes. Treatment with pecan shell AE prevented the development of LP (43%), GSH and SOD depletion (33% and 109%, respectively) and ethanol-induced erythrocyte genotoxicity. Catalase activity in the liver was unchanged by ethanol but was increased by the extract (47% and 73% in AE and AE+Et, respectively). Therefore, pecan shells may be an economic agent to treat liver diseases related to ethanol consumption.

Protective effect of chrysin on carbon tetrachloride (CCl4)—induced tissue injury in male Wistar rats

Chrysin, a natural flavonoid has been reported to possess potent anti-inflammatory, anti-cancer and antioxidation properties. In the present study, we aimed to evaluate the putative protective effect of chrysin, an isoflavone, on carbon tetrachloride (CCl4)-induced toxicity in male Wistar rats. Intraperitoneal administration of CCl4 (2 ml/kg) to rats for 4 days resulted in significantly elevated ( p < 0.05) serum levels of glutamic oxaloacetic transaminase (SGOT), glutamic pyruvate transaminase (SGPT), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH), when compared to normal rats. In addition, the tissues (liver, kidney and brain) and haemolysate samples showed considerable increase in levels ( p < 0.05) of malondialdehyde (MDA) and lowered levels ( p < 0.05) of reduced glutathione (GSH), vitamin C and E when compared to values in normal rats. Quantitative analysis of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (Gpx) exhibited lower activities of these antioxidant enzymes in the tissues and haemolysate of CCl4-administered rats. The protective action of chrysin on CCl4-induced rat was demonstrated with SGPT, SGOT, ALP and LDH resuming to near normal levels, while the mean levels of GSH and of vitamin C and E were elevated, the mean activities of CAT, SOD and Gpx were enhanced and the mean level of MDA was lowered in the tissue and haemolysate samples when compared to the CCl4-exposed untreated rats. The expression of the iNOS gene appeared to be up-regulated in the liver and kidney samples of CCl4-exposed untreated rats, whereas in CCl4-exposed chrysin-treated rats, the mRNA transcript levels of iNOS approximated normal levels. These results strongly suggest that chrysin is able to prevent the oxidative damage induced by CCl4 in the liver, brain, kidney and haemolysate of male Wistar rats.

Protective effect of Allium neapolitanum Cyr. versus Allium sativum L. on acute ethanol-induced oxidative stress in rat liver

This study investigated the protective effect of Allium neapolitanum Cyr., a spontaneous species of the Italian flora, compared with garlic (Allium sativum L.) on liver injury induced by ethanol in rats. Male albino Wistar rats were orally treated with fresh Allium homogenates (leaves or bulbs, 250 mg/kg) daily for 5 days, whereas controls received vehicle only. At the end of the experimental 5-day period, the animals received an acute ethanol dose (6 mL/kg, i.p.) 2 hours before the last Allium administration and were sacrificed 6 hours after ethanol administration. The activities of catalase (CAT), superoxide dismutase (SOD), and glutathione reductase (GR) and the levels of malondialdehyde (MDA), ascorbic acid (AA), and reduced (GSH) and oxidized glutathione in liver tissue were determined. Administration of both Allium species for 5 days (leaves or bulbs) led to no statistical variation of nonenzymatic parameters versus the control group; otherwise Allium treatment caused an increase of GSH and AA levels compared with the ethanol group and a diminution of MDA levels, showing in addition that A. neapolitanum bulb had the best protective effect. Regarding to enzymatic parameters, GR and CAT activities were enhanced significantly compared with the ethanol group, whereas SOD activity showed a trend different from other parameters estimated. However, the treatment with both Allium species followed by acute ethanol administration reestablished the nonenzymatic parameters similar to control values and enhanced the activities of the enzymes measured. These results suggest that fresh Allium homogenates (leaves or bulbs) possess antioxidant properties and provide protection against ethanol-induced liver injury.

Superoxide dismutase mRNA and protein level in human colorectal cancer

Impairments of antioxidant enzyme expression are often concomitant with the onset of cancer. Due to epigenetic factors causing an inflammatory state the gastrointestinal tract can become exposed to reactive oxygen species. The purpose of our work was to evaluate mRNA and protein levels of superoxide dismutase isoenzymes in human colorectal adenocarcinoma due to its clinical advancement, and in colorectal cancer liver metastases. Evaluation of SOD expression in regard to CRC advancement, seems useful for clinical applications due to different tumor cells sensitivity to reactive oxygen species based treatment. Studies were conducted on a group of 27 patients: 15 diagnosed with colorectal adenocarcinoma and 12 diagnosed with colorectal cancer liver metastases. The mRNA level was determined by RT-PCR, and protein level by Western blotting. We observed significant (P≤0.05) changes of mRNA and protein level of SOD isoenzymes in subsequent stages of colorectal adenocarcinoma advancement and in colorectal cancer liver metastases. Differences in mRNA and protein level of SOD isoenzymes in colorectal adenocarcinoma and its liver metastases indicates that SOD participate in adaptation of tumor cells to oxidative stress, and maintain certain level of ROS, necessary for appropriate cell proliferation. Expression of superoxide dismutase isoenzymes seems to be regulated not only at transcriptional level, but also posttranscriptional.

Antioxidant effect of 2-hydroxy-4-methoxy benzoic acid on ethanol-induced hepatotoxicity in rats

Alcoholic liver disease (ALD) is one of the most common diseases in society. A large number of studies are in progress to identify natural substances that are effective in reducing the severity of ALD. 2-Hydroxy-4-methoxy benzoic acid (HMBA), the active principle of Hemidesmus indicus, an indigenous Ayurvedic medicinal plant in India, is expected to significantly inhibit the development of liver injury in ethanol administration. It is expected to reduce the severity of liver damage in terms of body weight, hepatic marker enzymes, oxidative stress, antioxidant status and histological changes in ethanol-induced hepatotoxic rats. Hepatotoxicity was induced by administering 20% ethanol (5 g kg−1 daily) for 60 days to male Wistar rats, which resulted in significantly decreased body weight and an increase in liver-body weight ratio. The liver marker enzymes aspartate transaminase, alanine transaminase, alkaline phosphatase, γ-glutamyl transpeptidase and lactate dehydrogenase were elevated. In addition, the levels of plasma, erythrocyte and hepatic thiobarbituric acid reactive substances, hydroperoxides and conjugated dienes were also elevated in ethanol-fed rats as compared with those of the experimental control rats. Decreased activity of superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, vitamin C and α-tocopherol was also observed on alcohol administration as compared with experimental control rats. HMBA was co-administered at a dose of 200 μgkg−1 daily for the last 30 days of the experiment to rats with alcohol-induced liver injury, which significantly increased body weight, significantly decreased the liver-body weight ratio, transaminases, alkaline phosphatase, γ-glutamyl transpeptidase and lactate dehydrogenase, significantly decreased the levels of lipid peroxidative markers, significantly elevated the activity of enzymic and non-enzymic antioxidants in plasma, erythrocytes and liver and also increased levels of plasma and liver vitamin C and α-tocopherol at the end of the experimental period as compared with untreated ethanol-administered rats. The histological changes were also in correlation with the biochemical findings. The results suggest that HMBA administration may afford protection against ethanol-induced liver injury in rats.

Hepatoprotective effect of chrysin on prooxidant-antioxidant status during ethanol-induced toxicity in female albino rats

Objectives

To evaluate the effect of chrysin, a natural, biologically active compound extracted from many plants, honey and propolis, on the tissue and circulatory antioxidant status, and lipid peroxidation in ethanol-induced hepatotoxicity in rats.

Methods

Rats were divided into four groups. Groups 1 and 2 received isocaloric glucose. Groups 3 and 4 received 20% ethanol, equivalent to 5 g/kg bodyweight every day. Groups 2 and 4 received chrysin (20 mg/kg bodyweight) dissolved in 0.5% dimethylsulfoxide.

Key findings

The results showed significantly elevated levels of tissue and circulatory thiobarbituric acid reactive substances, conjugated dienes and lipid hydroperoxides, and significantly lowered enzymic and non-enzymic antioxidant activity of superoxide dismutase, catalase and glutathione-related enzymes such as glutathione peroxidase, glutathione reductase, glutathione-S-transferase, reduced glutathione, vitamin C and vitamin E in ethanol-treated rats compared with the control. Chrysin administration to rats with ethanol-induced liver injury significantly decreased the levels of thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes, and significantly elevated the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and the levels of reduced glutathione, vitamin C and vitamin E in the tissues and circulation compared with those of the unsupplemented ethanol-treated rats. The histological changes observed in the liver and kidney correlated with the biochemical findings.

Conclusions

Chrysin offers protection against free radical-mediated oxidative stress in rats with ethanol-induced liver injury.

Evidence of overestimation of rate constants for the superoxide trapping by nitrones in aqueous media

Since major disagreements exist regarding the kinetics of superoxide trapping by nitrones, the underlying theory of one of the most popular method used in these studies was reinvestigated. It involves a competition between the nitrone of interest and a superoxide scavenger, and implies that the superoxide spontaneous dismutation, the spin adduct decay, and the consumption of the competitor during the course of the experiments are negligible events. Evidences of the importance of these three unduly neglected reactions are given, and errors connected to their omission are estimated. Hence this Stern-Volmer-like method should be avoided in the determination of rate constants for the trapping of superoxide by nitrones.

Does chronic ethanol intake cause chronic pancreatitis?: evidence and mechanism

OBJECTIVES

To demonstrate the relationship between prolonged alcohol intake and chronic pancreatitis.

METHODS

Wistar rats were fed diet containing 25% concentration (vol/vol) of ethanol for 6 months. Cholecystokinin (CCK) was quantified by radioimmunoassay. Immunohistochemistry was used to detect alpha-smooth muscle actin, cyclooxygenase 2, and toll-like receptor 4 in rat pancreas. Western-blot was used to quantitatively determine the expression of nuclear factor kappaB and the above inflammatory markers. Pancreatic collagen content was quantified by measuring OH-proline. Superoxide dismutase was measured by colorimetric method.

RESULTS

In contrast to the control group, there was little histological change in pancreatic tissue but obvious ultrastructural changes in acinar cells of the ethanol group. Cholecystokinin, amylase, and lipase were found reduced in the ethanol group. Chronic ethanol intake did not elicit any change in the expression of alpha-smooth muscle actin, cyclooxygenase 2, toll-like receptor 4, nuclear factor kappaB, pancreatic collagen, and superoxide dismutase.

CONCLUSIONS

Long-term alcohol consumption did not cause chronic pancreatitis but impaired exocrine pancreatic function. The mechanism behind it could be associated with decreased output of intestinal CCK and lower concentration of pancreatic CCK. Furthermore, the nonoxidative pathway of ethanol metabolism was probably involved in it.

N-acetylcysteine effects on genotoxic and oxidative stress parameters in cirrhotic rats with hepatopulmonary syndrome

The aim of this study was to evaluate the potential antioxidant effects of N-acetylcysteine in hepatopulmonary syndrome, a complication of cirrhosis, using an experimental model of common bile duct ligation in rats. Male Wistar rats were divided into four experimental groups: CBDL (animals submitted to common bile duct ligation); Sham (animals submitted to simulated common bile duct ligation); Sham + N-acetylcysteine, and CBDL + N-acetylcysteine. N-acetylcysteine (10 mg/kg, intraperitoneally) was administered for 2 weeks starting on day 14 after surgery. Some alterations in the liver integrity were investigated by evaluation of serum enzymes aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and arterial blood gases. Lipoperoxidation by thiobarbituric acid-reactive substances assay, superoxide dismutase activity and total nitrates was measured as parameters of oxidative stress, performed on lung homogenates. Micronucleus assay in bone marrow and comet assay in lung, liver and blood were performed to assess the genotoxic effects by oxidative stress. The results showed an improvement in the enzymatic parameters and arterial blood gases, a reduction of lipoperoxidation and in the total nitrates after treatment with N-acetylcysteine. Histological analysis showed vasodilatation in the lung, which was reversed by N-acetylcysteine. Micronuclei frequency and DNA damage in lung and liver were increased in the CBDL group. N-Acetylcysteine caused no genotoxic effect and did not influence the induction of micronucleus in bone marrow and DNA damage in lung and liver. The results suggest protective effects after treatment with N-acetylcysteine in cirrhotic rats with hepatopulmonary syndrome.

Antioxidant effect of Hemidesmus indicus on ethanol-induced hepatotoxicity in rats

The antioxidant effect of the ethanolic root extract of Hemidesmus indicus, an indigenous Ayurvedic medicinal plant used in soft drinks in India, was studied in rats with ethanol-induced hepatotoxicity. Administering 20% ethanol (5 g/kg of body weight/day) for 60 days to male Wistar rats resulted in significantly decreased body weight and increased liver/body weight ratio. The liver marker enzymes, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatae (ALP), gamma-glutamyl transpeptidase (GGT), and lactate dehydrogenase (LDH), were elevated. In addition, the levels of plasma, erythrocyte, and hepatic thiobarbituric acid-reactive substances (TBARS), hydroperoxides (LOOH), and conjugated dienes (CD) were also elevated in ethanol-fed rats as compared to those of the experimental control rats. Decreased activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reduced glutathione (GSH), vitamin C, and alpha-tocopherol (vitamin E) were also observed in ethanol-administered as compared to control rats. Ethanolic root extract of H. indicus was administered at a dose of 500 mg/kg of body weight/day for the last 30 days of the experiment to rats with ethanol-induced liver injury, which significantly increased body weight, significantly decreased the liver/body weight ratio, AST, ALT, ALP, GGT, and LDH activities, and also the levels of TBARS, LOOH, and CD, significantly elevated the activities of SOD, CAT, GPx, and GSH in plasma, erythrocytes, and liver, and also increased levels of plasma and liver vitamin C and vitamin E at the end of the experimental period as compared to those of untreated ethanol-administered rats. Thus, our data indicate that treatment with H. indicus extract offers protection against free radical-mediated oxidative stress in plasma, erythrocytes, and liver of animals with ethanol-induced liver injury.

Hemidesmus indicus protects against ethanol-induced liver toxicity

Alcoholic liver disease (ALD) is one of the most common diseases in modern society. A large number of studies are in progress aiming to identify natural substances that would be effective in reducing the severity of ALD. Although there are currently a number of drugs on the market, their long-term use can have numerous side effects. Hemidesmus indicus is an indigenous Ayurvedic medicinal plant used in soft drinks in India. In this study, we examined the effects of its ethanolic root extract on experimental liver damage in order to evaluate its hepatoprotective effects against hepatotoxicity induced in rats by ethanol at a dosage of 5 g/kg body weight for 60 days. The H. indicus root extract was given at a dose of 500 mg/kg body weight for the last 30 days of the experiment. The animals were monitored for food intake and weight gain. The liver was analysed for the degree of lipid peroxidation using thiobarbituric acid reactive substances (TBARS) and antioxidant status using the activities of glutathione-dependent enzymes. The degree of liver damage was analysed using serum marker enzyme activities, the total protein, albumin, globulin, ceruloplasmin and liver glycogen contents, and the A/G ratio. The Fourier transform infrared spectra (FT-IR) of the liver tissues were recorded in the region of 4000-400 cm(-1). The ethanol-fed rats showed significantly elevated liver marker enzyme activities, lipid peroxidation levels and reduced antioxidant levels as compared to the control rats. Oral administration of H. indicus for the latter 30 days resulted in an increased food intake and weight gain, decreased TBARS levels, near normal levels of glutathione-dependent enzymes, increased total protein, albumin, globulin and liver glycogen contents, an increased A/G ratio, and decreased liver marker enzyme activities and ceruloplasmin levels. The relative intensity of the liver FT-IR bands for the experimental groups were found to be altered significantly (p < 0.05) compared to the control samples. For the group that had H. indicus co-administered with ethanol, the intensity of the bands was near normal. Moreover, the results of the FT-IR study correlated with our biochemical results.

In Vitro effect of D-004, a lipid extract of the ground fruits of the Cuban royal palm (Roystonea regia), on rat microsomal lipid peroxidation

D-004 is a lipid extract of the fruits of the Cuban royal palm (Roystonea regia) containing a mixture of saturated fatty acids. D-004 inhibits prostate hyperplasia (PH) induced with testosterone, in rodents. Since fatty acids inhibit lipid peroxidation (LP), this study investigated whether D-004 prevents in vitro LP. D-004 (0.9-1000 microg/mL) markedly and dose-dependently inhibited in vitro iron-induced LP in native brain and liver microsomes. D-004 showed hydroxyl radical scavenging activity, which could explain partially its antioxidant effect on microsomal iron-induced LP, but it was unable to scavenge superoxide and ABTS radicals, indicating a limited radical scavenging activity. Also, D-004 inhibited CCl4-mediated LP in active liver microsomes through a decreased generation of radical species rather than a radical trapping action on CCl(4)-derived radical species. D-004 also inhibited lipooxygenase (LOX) and cyclooxygenase (COX) activities, and the generation of protein-associated carbonyl groups after LP. Since increased oxidative stress has been linked to PH, the antioxidant effect of D-004 shown here could contribute to explaining its beneficial effects on T-induced PH in rodents. Nevertheless, this study shows only in vitro results. Further studies should investigate whether D-004 also exhibits antioxidant effects in vivo.

Role of the GABA-A system in estrogen-induced protection against brain lipid peroxidation in ethanol-withdrawn rats

BACKGROUND

Our previous study showed that 17 beta-estradiol (E2) treatment protects against cerebellar neuronal death and related motor deficits in ethanol-withdrawn rats, in part through the GABAergic system. In this study, we examined the effect of the GABA-A antagonist bicuculline on the neuroprotective effect of E2 by assessing the oxidative marker thiobarbituric acid reactive substances (TBARS) during ethanol withdrawal (EW).

METHODS

Ovariectomized animals that had implants of E2 (EW/E2) or oil (EW/Oil) pellets received liquid ethanol (7.5% w/v) or dextrin for 7 days by gavage. The GABA-A antagonist bicuculline (1.25 mg/kg) was administered (three times a day intraperitoneally) for 4 days starting 3 days before the onset of EW. After testing for overt EW signs at 7 hr of EW, one set of the animals was immediately killed for the collection of the cerebellum, hippocampus, and cortex. The brain homogenates were further processed for TBARS assay to detect TBARS in the presence or absence of FeCl(3). For assessing motor capacity, the other set of animals was tested for the latency to fall from a rotarod after 1 week of EW.

RESULTS

The EW/Oil animals had enhanced endogenous and FeCl(3)-stimulated TBARS levels in the cerebellum and the hippocampus in a manner potentiated by bicuculline but inhibited by E2. Bicuculline counteracted the protective effect of E2 when administered along with E2. Pearson correlation coefficients indicated that the latency to fall from the rotarod covaried with TBARS levels in the cerebellum and the hippocampus.

CONCLUSION

These data suggest that E2 protects against lipid peroxidation in vulnerable brain areas of ethanol-withdrawn rats, in part through the GABAergic system.

Supplementation of Pueraria radix water extract on changes of antioxidant enzymes and lipid profile in ethanol-treated rats

BACKGROUND

Water extract of Pueraria radix (PRWE), traditional oriental medicinal plant, may have an effect on the activity of hepatic antioxidant enzymes and lipid profile in ethanol-treated rats.

METHODS

Male Sprague-Dawley rats were divided into control, ethanol, PRWE and ethanol-PRWE supplemented groups. Twenty-five percent (v/v) ethanol (5 g/kg body weight) was orally administered once a day for 5 weeks. The PRWE was supplemented in a diet based on 1500 mg of raw PRWE/kg body weight/day.

RESULTS

Ethanol feeding resulted in a higher alcohol dehydrogenase (ADH) activity and lower aldehyde dehydrogenase (ALDH) activity. After PRWE supplementation, both activities were increased. The PRWE supplementation resulted in a significant decrease in the plasma and liver total cholesterol concentrations in the ethanol-treated rats. Ethanol administration significantly lowered the activities of hepatic superoxide dismutase (SOD) and catalase (CAT), whereas it increased the plasma and hepatic thiobarbituric acid reactive substances (TBARS) and the hepatic glutathione peroxidase (GSH-Px) activities. However, PRWE supplementation resulted in a significant increase in the SOD and CAT activities and a significant decrease in the TBARS and the GSH-Px activities in the ethanol-treated rats.

CONCLUSION

PRWE can contribute to alleviating the adverse effect of ethanol ingestion by enhancing the lipid metabolism as well as the hepatic antioxidant defense system.

Oxidative stress and antioxidants in patients with cardiogenic shock complicating acute myocardial infarction

BACKGROUND

Lipid peroxidation and derived oxidized products are being intensively investigated because of their potential to cause injury and because of their pathogenic role in several diseases. The view that an excess of lipid peroxidation products is present and is relevant in the pathogenesis of cardiogenic shock-induced damage has still not received definitive support.

METHODS

To evaluate the extent of lipid peroxidation, the status of enzymatic and nonenzymatic antioxidants in patients with cardiogenic shock that complicate acute myocardial infarction (AMI) and to compare with normal subjects.

RESULTS

Compared with normal subjects, cardiogenic shock patients had higher malondialdehyde, conjugated dienes and reduced activities of erythrocyte antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lower concentrations of reduced glutathione (GSH) in erythrocyte and in plasma GSH, vitamin C, vitamin E and in beta-carotene.

CONCLUSIONS

Cardiogenic shock is associated with greater than normal lipid peroxidation and with an imbalance in antioxidants' status. These results indicate that low activities of SOD, CAT, GPx and low concentrations of GSH, vitamin C, vitamin E and beta-carotene in the circulation of patients with cardiogenic shock complicating AMI may be due to increased utilization to scavenge lipid peroxides. Decrease in plasma concentrations of GSH, vitamin E and beta-carotene seems to be responsible for the elevation of lipid peroxidation in cardiogenic shock complicating AMI compared with MI.

Quercetin, a flavonoid antioxidant, prevents and protects against ethanol-induced oxidative stress in mouse liver

This study evaluates whether quercetin (25, 50 and 75 mg/kg body weight) treatment has a protective effect on the pro-oxidant-antioxidant state following chronic ethanol treatment in mice. Pretreatment (quercetin 25, 50 and 75 mg/kg body weight for 15 d+co-treatment of ethanol 18%+quercetin for 15 d and ethanol 18% for the 15 d) increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH) in comparison to the ethanol group. No significant differences from the ethanol group were observed in the group after post-treatment (ethanol 18% for 30 d+quercetin 25, 50 and 75 mg/kg body weight for 15 d) with quercetin. A significant increase in lipid peroxidation (malondialdehyde, MDA) products was observed in liver tissue after administration of ethanol, which was attenuated by pre- and post-treatment with a high dose of quercetin. GSH levels increased and oxidized glutathione (GSSG) levels decreased in groups of ethanol-exposed mice that received quercetin for 15 d prior to ethanol exposure. In conclusion, pre-treatment of quercetin may protect against ethanol-induced oxidative stress by directly quenching lipid peroxides and indirectly by enhancing the production of the endogenous antioxidant GSH. There was no protective effect on post-treatment with quercetin.

Mechanisms of transformation of the antioxidant kaempferol into depsides. Gamma-radiolysis study in methanol and ethanol

In this study, we irradiated the antioxidant kaempferol in ethanol and methanol solutions with gamma rays at doses ranging from 0.2-20 kGy. NMR and ES-MS spectroscopy were used to identify radiolysis products. Two depsides, [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) methyl acetate and [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) ethyl acetate, were the major compounds of kaempferol degradation in methanol and in ethanol, respectively. Other products formed in low concentrations were identified as [4-hydroxyphenyl](oxo) methyl acetate, [4-hydroxyphenyl](oxo) ethyl acetate, and depside [2-[(4'-hydroxybenzoyl)oxy]-4,6-dihydroxyphenyl](oxo) acetic acid. The formation of the latter was observed in both solvents. We propose degradation mechanisms that suggest that (.)CH(2)OH and CH(3)(.)CHOH, produced by solvent radiolysis, react with the 3-OH kaempferol group because of its high H-donor capacity. pi-Electron delocalization in the flavonoxy formed after the first H-transfer leads to C-ring opening and consequently to the formation of depsides. G calculation of the degradation products and of (.)CH(2)OH and CH(3)(.)CHOH radicals confirmed the proposed mechanism of kaempferol radiolysis. The rate constants for the reaction between kaempferol and these free radicals were also calculated. Formation of depside has also been observed in many studies of the oxidation of flavonoids; those studying human metabolism have suggested similar redox transformation of flavonols. The antioxidant activities of radiolysis products were evaluated and compared to those of kaempferol.

Effects of Puerariae Flos and Puerariae Radix extracts on antioxidant enzymes in ethanol-treated rats

This study was performed to investigate the effect of Puerariae Flos (PF) and Puerariae Radix (PR) water extracts on the activities and mRNA expression of three hepatic antioxidant enzymes in ethanol-treated rats. Male Sprague-Dawley rats were divided into four groups, a control, ethanol-treated, ethanol plus PF-treated, and ethanol plus PR-treated group with seven rats per group. Ethanol (25 % v/v, 5 g/kg body weight) was orally administered once a day for 5 weeks. The PF and PR water extracts were supplemented in a diet based on 1.2 g of raw PF or PR/kg body weight/day. Ethanol administration without the PF or PR supplement significantly lowered the activities of hepatic Cu/Zn SOD and catalase (CAT), whereas it increased the hepatic GSH-Px activity. However, the PF and PR supplementation resulted in a significant increase in the Cu/Zn SOD and/or CAT activities and a significant decrease in the GSH-Px activity in the ethanol-treated rats. The mRNA levels of these antioxidant enzymes in the ethanol-treated rats were normalized to the control level by the PF or PR supplement. The hepatic glutathione content, which was significantly lower in the ethanol-treated group than in the control group, was also normalized to the control level by supplementing with either PF or PR. The PF or PR supplement resulted in lowering the hepatic malondialdehyde to the control level in the ethanol-treated rats.

Dietary glycine inhibits activation of nuclear factor kappa B and prevents liver injury in hemorrhagic shock in the rat

We investigated the effects of a glycine-containing diet (5%) on liver injury caused by hemorrhagic shock and resuscitation in rats. Anesthetized rats were bled to a mean arterial blood pressure of 35-40 mm Hg for 1 h and then resuscitated with 60% of shed blood and lactated Ringer's solution. Feeding the rats glycine significantly reduced mortality, the elevation of plasma transaminase levels and hepatic necrosis. The increase in plasma TNFalpha and nitric oxide (NO) was also blunted by glycine feeding. Hemorrhagic shock resulted in oxidative stress (significant elevations in TBARS and in the oxidized/reduced glutathione ratio) and was accompanied by a reduced activity of the antioxidant enzymes Mn- and Cu,Zn-superoxide dismutase, glutathione peroxidase and catalase, overexpression of inducible NO synthase (iNOS), and activation of nuclear factor kappa B (NF-kappaB). Glycine ameliorated oxidative stress and the impairment in antioxidant enzyme activities, inhibited NF-kappaB activation, and prevented expression of iNOS. Dietary glycine blocks activation of different mediators involved in the pathophysiology of liver injury after shock.

[Alcohol and oxidative stress]

There is accumulating evidence pointing oxidative stress as a mechanism of ethanol toxicity. Oxidative stress takes place when the balance between the antioxidant defenses and the generation of reactive oxygen species (ROS) is tipped in favour of the latter. Ethanol metabolism is directly involved in the production of ROS, but ethanol also participated to the formation of an environment favourable to oxidative stress such as hypoxia, endotoxemia and cytokine release. Following ethanol intoxication, balance between prooxidants and antioxidants is disturbed to such an extent that it results in an oxidative damage of biomolecules. The ability of ethanol to induce peroxidation of membrane lipids is widely reviewed in literature. More recently it has also been described that ethanol can oxidize proteins and ADN. In this review, is also discussed the impairment of cellular function resulting from this situation of oxidative stress.

Chronic ethanol and nicotine interaction on rat tissue antioxidant defense system

Ethanol consumption and cigarette smoking are common in societies worldwide and have been identified as injurious to human health. This study was undertaken to examine the interactive effects of chronic ethanol and nicotine consumption on the antioxidant defense system in different tissues of rat. Male Fisher-344 rats were divided into four groups of five animals each and treated for 6.5 weeks as follows: (1) Control rats were administered normal saline orally; (2) ethanol (20% [wt./vol.]) was given orally at a dose of 2 g/kg; (3) nicotine was administered subcutaneously at a dose of 0.1 mg/kg; and (4) a combination of ethanol plus nicotine was administered by the route and at the dose described above. The animals were killed 20 h after the last treatment, and liver, lung, kidney, and testes were isolated and analyzed. Chronic ingestion of ethanol resulted in a significant depletion of glutathione (GSH) content in liver, lung, and testes, whereas chronic administration of nicotine significantly depleted GSH content in liver and testes. The combination of ethanol plus nicotine resulted in a significant depletion of GSH content in liver, lung, and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased superoxide dismutase (SOD) activity in liver and decreased SOD activity in kidney. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly decreased catalase (CAT) activity in liver and increased CAT activity in kidney and testes. Chronic ingestion of ethanol resulted in a significant decrease in glutathione peroxidase (GSH-Px) activity in liver and kidney, whereas a combination of ethanol plus nicotine increased GSH-Px activity in liver and decreased GSH-Px activity in kidney and testes. Ethanol, nicotine, or a combination of ethanol plus nicotine significantly increased lipid peroxidation, respectively, in liver. It is suggested that prolonged exposure to ethanol and nicotine produce similar, and in some cases additive, oxidative tissue injuries in rat.

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.

Effects of parenteral nutrition supplemented with glutamine or glutamine dipeptides on liver antioxidant and detoxication systems in rats

Our aim was to determine the effects of glutamine or alanyl glutamine parenteral supplementation on the liver oxidant/antioxidant balance and on cytochrome-P450-mediated detoxication in rats. Animals were infused for 5 d with standard total parenteral nutrition (TPN), glutamine-enriched TPN, or alanyl glutamine-enriched TPN. The hepatic concentration of glutathione was reduced, and the levels of thiobarbituric-acid-reactive substances (TBARS) were increased in animals receiving standard TPN. Both glutamine and alanyl glutamine supplementation normalized glutathione, but thiobarbituric-acid-reactive substance concentration was only decreased by ananyl glutamine. This effect was parallel to a partial recovery of the activity of antioxidant enzymes. Cytochrome-P450 liver content, cytochrome-P450-dependent monooxygenases, and antipyrine clearance were not modified by glutamine or alanyl glutamine. Our data suggest a better protection against free radicals by alanyl glutamine supplementation and an absence of effects of both glutamine and alanyl glutamine on liver oxidative metabolism.

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.

Dose and time dependent effects of ethanol on antioxidant system in rat testes

This study was designed to investigate the dose as well as time dependent effects of ethanol on testicular antioxidant defense system in rats. Male Fischer 344 rats were administered ethanol at a dose of 2, 4, and 6 gm/kg orally and control received equal volume of saline and sacrificed 1 h after ethanol ingestion. For time course study, animals were administered ethanol 4 g/kg orally and sacrificed at 1.5, 2, 4, and 6 h after ethanol ingestion. Testicular ethanol concentration increased with increasing doses of ethanol. Copper zinc-superoxide dismutase (CuZn-SOD) activity significantly decreased in the testes of rats treated with increasing doses of ethanol whereas manganese-superoxide dismutase (Mn-SOD) activity significantly increased in a dose dependent manner (181, 186, and 195% of control, respectively). Testicular glutathione (GSH) and malondialdehyde (MDA) levels did not significantly alter with increasing doses of ethanol one hour after ethanol ingestion. Ethanol concentration decreased in the testes with an increase in time after ethanol ingestion. Testicular CuZn-SOD activity significantly decreased whereas Mn-SOD activity increased with an increase in time after ethanol ingestion. Testicular catalase (CAT) activity significantly decreased at 2 h postethanol ingestion. Testicular MDA levels significantly increased at 4 and 6 h after ethanol ingestion indicating that end product of lipid peroxidation. MDA, takes considerable time to form in the testes. A significant decrease in the ratios of CAT/Mn-SOD and glutathione peroxidase (GSH-Px)/Mn-SOD in the testes of rat suggests the ability of mitochondria to scavenge reactive oxygen species (ROS). It is suggested that antioxidant enzyme ratios may be used as an important parameter to determine ethanol induced oxidative stress in the tissues.

Dose- and time-dependent effects of ethanol on plasma antioxidant system in rat

This study investigates the dose- as well as time-dependent effects of ethanol ingestion on antioxidant system and lipid peroxidation in plasma of the rat. The plasma ethanol concentrations were 154+/-18, 231+/-53, and 268+/-49 mg/dl 1 h after oral ethanol doses of 2, 4, and 6 g/kg, respectively. Superoxide dismutase (SOD) (71%, 56%, and 41 % of control) and glutathione reductase (GR) (71%, 66%, and 55% of control) activity in plasma were significantly decreased in a dose-dependent manner. Catalase (CAT)/SOD and glutathione peroxidase (GSH-Px)/SOD ratios were significantly increased whereas GR/GSH-Px ratio was significantly decreased with increasing dose of ethanol. In a time course study, plasma ethanol concentrations were 177+/-9.7, 143+/-11, 99+/-17, and 26+/-11 mg/dl at 1.5, 2, 4, and 6 h after an oral dose (4 g/kg) of ethanol in rat indicating time-dependent elimination of ethanol. Plasma SOD and GSH-Px activity significantly increased 4-6 h whereas GR activity significantly decreased 2-4 h after ethanol ingestion. The ratio of GR/GSH-Px and the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) in plasma decreased at 1.5-6 h after ethanol ingestion. Plasma malondialdehyde (MDA) levels significantly elevated with respect to an increase in time after ethanol ingestion, indicating time-dependent augmentation of lipid peroxidation. The data indicate that ethanol ingestion perturbs the plasma antioxidant system in a dose- and time-dependent manner. The significant changes in the ratios of CAT/SOD, GSH-Px/SOD, GR/GSH-Px, and GSH/GSSG in plasma may be used as an index of alcohol-induced oxidative stress.

Effect of an NMDA receptor antagonist and a ganglioside GM1 derivative upon ethanol-induced modification of parameters of oxidative stress in several brain regions

Dietary administration of ethanol to rats for 2 weeks was able to depress levels of glutathione (GSH) and Cu/Zn superoxide dismutase (SOD) in several brain regions. This was indicative of the generation of excess levels of reactive oxygen in treated animals. The potentially protective effect of both an NMDA receptor blocker (MK-801) and an internally esterified derivative of ganglioside GM1 (AGF2) upon ethanol-induced changes in these indices of oxidative stress, was studied. Both of these agents are reported to have neuroprotective properties, but neither was able to prevent ethanol-induced reduction of GSH and SOD levels in any brain area studied. In fact, both agents depressed SOD and GSH levels in midbrain independently of ethanol. MK-801 had a pronounced pro-oxidant potential, and when administered in combination with ethanol. GSH and SOD were reduced in midbrain and striatum to levels below those obtained with either agent alone. The pro-oxidant properties of ethanol may thus act independently of its actions upon the NMDA receptor. The protective properties of NMDA receptor inhibitors or gangliosides cannot be attributed to any antioxidant effect.

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.