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Abstract

Aging and ethanol induce oxidative stress due to increased prooxidant production and decreased antioxidative capacity. The aim was to investigate the influence of aging on oxidative stress in liver, stomach and pancreas in acute ethanol intoxication. Adult (3 months) and old (18 months) male Wistar rats were divided into the following groups: control (control group rats aged 3 months (C3) and control group rats aged 18 months (C18)) and ethanol-treated groups (ethanol-treated 3-month-old rats (E3) and ethanol-treated 18-month-old rats (E18)). Ethanol was administered in five doses of 2 g/kg at 12-h intervals by orogastric tube. Tissue samples were collected for the determination of oxidative stress parameters. Malondialdehyde (MDA) concentration was increased in all the experimental groups and investigated organs versus C3 group ( p < 0.01). The highest MDA level was observed in the stomach in E18 group when compared with C18 and E3 groups ( p < 0.01). Activity of total superoxide dismutase (SOD) and its isoenzymes (copper-/zinc-SOD and manganese-SOD) in E18 group was significantly decreased when compared with E3 and C18 groups ( p < 0.01). Nitrates and nitrites (NO _x ) concentration was increased in stomach and pancreas for all the groups when compared with C3 group ( p < 0.01). Hepatic, gastric and pancreatic NO _x level was significantly increased in E18 group when compared with E3 group ( p < 0.01). Moreover, level of NO _x in liver and pancreas in E18 group was significantly increased when compared with C18 group ( p < 0.01). Aging potentiates ethanol-induced oxidative stress in liver, stomach and pancreas due to increased lipid peroxidation and nitrosative stress and decreased antioxidative tissue capacity.

Keywords

Aging ethanol oxidative stress digestive system rats

Introduction

Ethanol, an active compound of alcoholic beverages, is responsible for morphological and functional damages of different tissues and organs, including hepatogastrointestinal tract.^1

–7 Acute and chronic ethanol treatment has been shown to increase the production of reactive oxygen species (ROS), lower cellular antioxidant levels and enhance oxidative stress in many tissues, especially the liver.^3,6,7 Numerous pathways have been suggested as playing a key role in how ethanol induces oxidative stress and contributes to alcoholic liver disease (ALD), chronic gastritis, as well as acute and chronic pancreatitis. Some of these include redox state changes, production of the reactive product acetaldehyde, damage to mitochondria, direct or membrane effects caused by hydrophobic ethanol, ethanol-induced hypoxia, ethanol induction of cytochrome P4502E1 (CYP2E1), ethanol mobilization of iron and effects on antioxidant enzymes and chemicals, particularly mitochondrial and cytosolic glutathione.^3,8,9 The most important source of ROS in liver is CYP-dependent monooxygenase.¹⁰ Other sources of ROS are Kupffer cells and neutrophils that infiltrated liver during alcoholic hepatitis.³ It was also demonstrated that ethanol activates inducible nitric oxide synthase (iNOS) in Kupffer cells. Together with superoxide anion (O₂ ⁻), nitric oxide (NO) is responsible for the production of very reactive peroxynitrite that disturbs cell functions.¹¹ In particular, under chronic and heavy ethanol intake conditions, CYP2E1 is increased several fold contributing to the lipid peroxidation associated with ALD.⁹ Similarly, chronic ethanol administration may lead to acute and chronic pancreatitis, due to increased activity of pancreatic CYP2E.¹² ^–14 In addition, chronic ethanol consumption promotes activation of catalase and CYP-dependent monooxygenase in upper parts of digestive system, resulting in ROS production and lipid peroxidation. On the other hand, oxidative stress associated with acute and chronic alcoholism disturbs energy metabolism of mitochondria, especially in parietal cells of gastric mucosa, which is responsible for stomach injury.^4,15 Moreover, ethanol-induced ROS generation leads to endothelial dysfunction, microcirculatory disorders and ischemia of gastric mucosa.¹⁵

Aging is a complex biological process characterized by progressive functional and structural deterioration of multiple organ systems after the reproductive phase of life.¹⁶ The free radical theory of aging, which was first introduced in 1956 by Harman,¹⁷ is probably the most complex approach to explain the process of aging. It is based on the fact that the random deleterious effects of free radicals produced during aerobic metabolism cause damage to DNA, lipids and proteins and accumulate over time.^18
–20 The cell repairs much of the damage done to nuclear DNA, but mitochondrial DNA (mtDNA) cannot be readily fixed. Therefore, extensive mtDNA damage accumulates over time and shuts down mitochondria, causing cells to die and the organism to age.¹⁸ Under such conditions, in liver, one can observe volume alteration, accumulation of lipofuscin in hepatocytes and reduction in detoxification capacity.²¹ Simultaneously, atrophy of pancreatic tissue followed by fatty infiltration and fibrosis also occur.²² Evidence from various animal models and studies in humans indicate that these structural and functional alterations are mostly a consequence of increased oxidant generation and/or reduced antioxidant capacity.²¹ Besides, aging leads to increased lipid peroxidation and ROS generation in gastric mucosa, too.²³

Because oxidative stress contributes to ethanol-induced injury of digestive system to a great extent, one can postulate impact of free radicals on diverse age groups susceptibility to ethanol effects. Therefore, the aim of the present study was to investigate the influence of aging on oxidative stress in liver, stomach and pancreas in acute ethanol intoxication in rats.

Materials and methods

Animals

The acute experiment was performed on adult, male Wistar rats with a body weight of 200–500 g, raised at Military Medical Academy (Belgrade, Serbia). Animals were kept under standard laboratory conditions (temperature of 22 ± 2°C, relative humidity of 50 ± 10% and 12/12 h light/dark cycle with lights turned on at 9.00 a.m.) and had free access to tap water and standard pelleted LM2 food (Veterinary Institute ‘Subotica’, Subotica, Serbia). All the experimental procedures were in full compliance with the Directive of the European Parliament and of the Council (2010/63/EU) and approved by The Ethical Committee of the Faculty of Medicine, University of Belgrade.

According to age, all animals (n = 28) were divided into two groups: adult (3 months old; n = 14) and old (18 months old; n = 14). Having in mind the experimental protocol, both groups were divided into two subgroups (n = 7 each): (1) control group, treated with distilled water (control group rats aged 3 months (C3) and control group rats aged 18 months (C18), respectively); (2) ethanol-treated group (ethanol-treated 3-month-old rats (E3) and ethanol-treated 18-month-old rats (E18), respectively). Ethanol was administered in five doses of 2 g/kg at 12-h intervals by orogastric tube. For oral administration, ethanol (Sigma Aldrich Chem. Co., St Louis, Missouri, USA) was dissolved in distilled water in the concentration of 30% (v/v). This dose was chosen according to our studies, in which it induces oxidative stress in liver.^6,7 Control groups are treated with distilled water similarly. Rats were killed by cervical dislocation 12 h after the last dose of ethanol administration. Hepatic, gastric and pancreatic tissues were excised and stored as described below.

Sample preparation

For the biochemical analysis, liver, stomach and pancreatic samples were homogenized on ice in 0.25 M cold-buffered sucrose medium (Serva Feinbiochemica, Heidelberg, Germany), 10 M phosphate buffer (pH 7.0) and 1 mM EDTA; Sigma Chem. Co., St. Louis, Missouri, USA). The homogenates were centrifuged at 2000g for 15 min at 4°C. Crude sediments were dissolved in sucrose medium and centrifuged. The supernatants were transferred into the tubes and centrifuged at 3200g for 30 min at 4°C. Obtained sediments were dissolved in deionized water. After 1 h of incubation, the samples were centrifuged at 3000g for 15 min at 4°C and the supernatants were stored at −70°C. Proteins were determined by Lowry’s method using bovine serum albumin as the standard.²⁴

Biochemical analysis

Lipid peroxidation in investigated tissue homogenates was measured as malondialdehyde (MDA) production, assayed in the thiobarbituric acid reaction as described by Girotti et al.²⁵ The thiobarbituric acid with MDA forms yellow-colored complex, which can be measured spectrophotometrically at 533 nm. The results are expressed as micromole per milligram proteins in tissue homogenates.

Total superoxide dismutase (SOD; EC1.15.1.1) activity in liver, gastric and pancreatic tissues was measured spectrophotometrically, as an inhibition of epinephrine auto-oxidation at 480 nm. After the addition of 10 mM epinephrine (Sigma Chem. Co.), analysis was performed in the sodium carbonate buffer (50 mM, pH 10.2; Serva, Feinbiochemica) containing 0.1 mM EDTA (Sigma Chem. Co.). Samples for manganese-SOD (MnSOD) were previously treated with 8 mM potassium cyanide (Sigma Chem. Co.) and then analyzed as described.²⁶ The activity of copper-/zinc-SOD (CuSOD/ZnSOD) was calculated as a difference between total SOD and MnSOD activity.

The concentration of nitrites + nitrates (NO _x ), as a measure of NO production in the hepatic, gastric and pancreatic tissue, was determined using Griess reagent. After reduction in nitrates, total nitrites react with sulfanilamide and N-(1-naphtyl)-ethylenediamine to produce an azo dye, which can be measured spectrophotometrically at 492 nm (Hibbs et al., 1988).²⁷

Chemicals

All reagents and chemicals were of analytical grade or higher purity. Ethanol was purchased from Merck (Darmstadt, Germany).

Statistical analysis

Results are expressed as means ± SD. As the normal distribution of parameters was confirmed by Kolmogorov–Smirnov test, for testing the difference among groups, two-way analysis of variance (ANOVA) with Tukey’s post hoc test was used. The difference was considered statistically significant if p < 0.05. Statistica 7.0 was used for the statistical analysis.

Results

Our study shows that MDA level in rats was significantly higher in E3 and C18 group in all the investigated organs in comparison with C3 group (100%; p < 0.01). Comparing individual organs, it was observed that this increase in E3 group was more pronounced in stomach (201.92 ± 30.77%) and in pancreas (197.99 ± 58.38%) in comparison with liver (130.59 ± 34.12%; p < 0.01). On the other hand, the increase in MDA level in C18 group was more pronounced in the pancreas (191.95 ± 54.36%) in comparison with the liver (140 ± 14.11%) and the stomach (128.36 ± 39.9%; p < 0.01). Similarly, in E18 group, MDA level in each organ was significantly higher than that in control group (100%; p < 0.01). This increase was more pronounced in the stomach (300 ± 50%) in comparison with pancreas (210.74 ± 47.65%) and liver (187.06 ± 34.12; p < 0.01). MDA level was higher in the stomach in E18 in comparison with C18 and E3 groups ( p < 0.01). In contrast, there was no significant difference in MDA level in liver and pancreas among these groups ( p > 0.05; Figure 1).

Figure 1.

The effects of ethanol and aging on MDA level in rat liver, stomach and pancreas. Ethanol was administered in five doses of 2 g/kg for every 12 h. MDA level was measured 24 h after the last dose of ethanol and is expressed as a relative change of value found in C3 group. Significance of the difference was estimated using ANOVA with Tukey’s post hoc test (*p < 0.01 vs. C3 group; ^# p < 0.01 vs. E3 group). MDA: malondialdehyde; C3: control group rats aged 3 months; C18: control group rats aged 18 months; E3: ethanol-treated 3-month-old rats; E18: ethanol-treated 18-month-old rats. ANOVA: analysis of variance.

Total SOD activity in E3 group was decreased in all the organs in comparison with C3 group (100%). More pronounced decrease in total SOD activity in the same group was observed in the stomach (70 ± 6.78%) and liver (62.28 ± 5.2%) in comparison with pancreas (91.83 ± 5.36%; p < 0.01). Similarly, total SOD activity in C18 and E18 groups was significantly lower in all the organs in comparison with control (100%; p < 0.01). In C18 group, there was no statistically significant difference in the total SOD activity of liver, gastric and pancreatic (77.49 ± 4.67%, 81.33 ± 6.27% and 81.91 ± 6.74%, respectively). On the other hand, decrease in SOD activity in E18 group was more pronounced in the liver (48.11 ± 4.49%) and stomach (47.01 ± 3.95%) in comparison with pancreas (72.79 ± 6.5%; p < 0.01). In E18 group, total SOD activity was significantly decreased when compared with E3 and C18 groups, with the most pronounced decrease in the liver and stomach ( p < 0.01; Figure 2).

Figure 2.

The effects of ethanol and aging on total SOD activity in rat liver, stomach and pancreas. Significance of the difference was estimated using ANOVA with Tukey’s post hoc test (*p < 0.01, **p < 0.05 vs. control group; ^† p < 0.01, ^†† p < 0.05 vs. C18 group; ^# p < 0.01 vs. E3 group). SOD: superoxide dismutase; ANOVA: analysis of variances; C18: control group rats aged 18 months; E3: ethanol-treated 3-month-old rats.

CuSOD/ZnSOD activity in C18 and E18 groups was significantly decreased in comparison with control (100%) in all the three organs ( p < 0.01). That decrease in C18 group was more pronounced in the liver (70.56 ± 4.6%) than in stomach (82.14 ± 5.77%) and pancreas (82.72 ± 7.14%; p < 0.01). In both the ethanol-treated groups (E3 and E18), decrease in CuSOD/ZnSOD activity was more pronounced in the liver (54.82 ± 4.52% and 45.98 ± 4.12%, respectively) and stomach (69.04 ± 4.57% and 44.91 ± 2.88%, respectively) when compared with pancreas (87.79±7.44% and 73.84 ± 6.6%, respectively; p < 0.01). CuSOD/ZnSOD activity was decreased in E18 group in comparison with C18 and E3 groups in all the investigated organs (Figure 3).

Figure 3.

The effects of ethanol and aging on CuSOD/ZnSOD activity in rat liver, stomach and pancreas. Significance of the difference was estimated using ANOVA with Tukey’s post hoc test (*p < 0.01, **p < 0.05 vs. C3; ^† p < 0.01, ^†† p < 0.05 vs. C18 group; ^# p < 0.01, ^## p < 0.05 vs. E3 group). CuSOD/ZnSOD: copper-/zinc-superoxide dismutase; ANOVA: analysis of variances; C3: control group rats aged 3 months; C18: control group rats aged 18 months; E3: ethanol-treated 3-month-old rats.

In C18 group, MnSOD activity in the liver (82.93 ± 8.3%), stomach (75.88 ± 5.32%) and pancreas (75.01 ± 3.98%) was significantly decreased when compared with C3 group ( p < 0.05, p < 0.01, respectively). Hepatic, gastric and pancreatic MnSOD activity in E18 group was significantly decreased in comparison with control (100%; 64.77 ± 6.66%, 61.2 ± 4.53% and 63.83 ± 4.79%, respectively; p < 0.01). Gastric MnSOD activity (76.49 ± 8.09%) was significantly decreased in E3 group when compared with C3 group ( p < 0.01). In contrast to MnSOD activity in stomach, its activity in liver and pancreas was significantly increased in comparison with control (177.79 ± 11.19% and 126.35 ± 10.86%, respectively; p < 0.01). However, in E18 group, MnSOD activity was decreased in comparison with E3 and C18 groups in all the investigated organs ( p < 0.05, p < 0.01, respectively; Figure 4).

Figure 4.

The effects of ethanol and aging on the MnSOD activity in rat liver, stomach and pancreas (percentage of C3). Significance of the difference was estimated using ANOVA with Tukey’s post hoc test (*p < 0.01, **p < 0.05 vs. C3 group. ^†† p < 0.05 vs. C18 group, ^# p < 0.01, ^## p < 0.05 vs. E3 group). ANOVA: analysis of variance; C3: control group rats aged 3 months; C18: control group rats aged 18 months; E3: ethanol-treated 3-month-old rats; MNSOD: manganese-SOD.

Nitrites level in E3, C18 and E18 groups was significantly higher in the liver and pancreas in comparison with C3 group (100%; p < 0.01). In C18 group, NO _x level was significantly higher in the liver (200 ± 18.75%) in comparison with pancreas (127.84 ± 28.69%) and stomach (107.61 ± 14.21%; p < 0.01). In both the ethanol-treated groups (E3 and E18), the increase in NO _x level was more pronounced in the liver (318.75 ± 25% and 371.87 ± 25%, respectively) and pancreas (271.3 ± 68.35% and 320.67 ± 72.99%, respectively) when compared with stomach (110.15 ± 16.24% and 134.01 ± 15.73%, respectively; p < 0.01). In relation with hepatic, gastric and pancreatic NO _x levels in E18 group was more pronounced when compared with E3 group. Similarly, liver and pancreatic NO _x level in E18 group was significantly higher than in C18 group ( p < 0.01; Figure 5).

Figure 5.

The effects of ethanol and aging on nitrates + nitrites (NO _x ) level in rat liver, stomach and pancreas. Significance of the difference was estimated using ANOVA with Tukey’s post hoc test (*p < 0.01 vs. C3, ^† p < 0.01 vs. C18, ^# p < 0.01 vs. E3). ANOVA: analysis of variance; C3: control group rats aged 3 months; C18: control group rats aged 18 months; E3: ethanol-treated 3-month-old rats.

Discussion

Considerable experimental evidence supports the idea that ROS play a key role in the pathophysiological process of major organs and tissue damage in aged rats.^28,29 Aging is normally associated with an increase in the level of oxidation. An imbalance between the formation and elimination of ROS and the development of oxidative stress plays a vital role in aging and age-associated diseases. ROS inflicts the proteins, lipids, carbohydrates and nucleic acids, thereby inactivates enzyme transporters, damages DNA and transcriptional machinery. Moreover, the intense production of free radicals leads to peroxidative changes that ultimately result in increased lipid peroxidation. MDA, an end product of lipid peroxidation, is used as a marker of tissue damage. Aging is attributed to be associated with increased destruction of membrane lipids leading to subsequent formation of peroxide radicals.²⁸ In the present study, aging leads to pronounced increase in MDA concentration in liver, stomach and pancreas, suggesting a possible role of age-induced lipid peroxidation in investigated tissue damage. Besides, results obtained from our study demonstrate that the most prominent increase in liver, gastric and pancreatic MDA concentration was observed in old rats treated with ethanol. These data also indicate that acute ethanol intoxication potentiates age-induced lipid peroxidation. Moreover, these results suggest that ethanol, when acutely administered, has synergistic effects with aging related to lipid peroxidation. Based on these data, it can also be suggested that lipid peroxidation may be an important mechanism of age- and ethanol-induced oxidative tissue damage. It is known that aging is characterized by oxidative modifications of the lipids and proteins that are the main membrane components. In this regard, an increase in MDA concentration in liver, pancreas and all over gastrointestinal tract in acute and chronic ethanol intoxication is reported.^{1,3,6

–10,12

–15} That is mainly due to the reactions of ROS with lipids and proteins.²⁹ Additionally, it is suggested that the changes in cell membrane charge are connected with changes in membrane composition. Thus, aging and ethanol intoxication are accompanied by changes in the composition of liver phospholipids, fatty acids and cholesterol, which leads to changes in membrane fluidity. Furthermore, both ROS and ethanol metabolite – acetaldehyde – can react with proteins and modify their structure. Thus, ROS reactions with proteins lead to peroxyl radical and hydroperoxide formation, while the reaction of lipid peroxidation products with proteins results in carbonyl group formation.^28,29 Besides, as a consequence of these reactions, protein fragmentation occurs, resulting in new functional groups, which may alter membrane electric charge. In addition, acetaldehyde can react with amino, sulfhydryl and another groups of peptides and proteins. The perturbation of the protein structure may greatly affect lipid–protein interactions. Cell membrane impairment caused by the modification of lipid and protein structure may be linked to the increased oxidative stress caused by an imbalance in the generation and neutralization of free radicals.^28,29

In our study, the greatest increase in MDA level was observed in the stomach of ethanol-treated rats. In this regard, several mechanisms are involved in gastric oxidative damage in acute ethanol intoxication, such as activation of alcohol dehydrogenase, aldehyde dehydrogenase, CYP2E1 and catalase.¹ Similarly, activation of CYP-dependent monooxygenase in the stomach and lower parts of gastrointestinal tract leads to the ROS formation as well as various potentially cancerogenic products of xenobiotic metabolism.^1,4,15

Findings of the present study indicate that aging induces the significant decrease in hepatic, gastric and pancreatic total SOD activity in comparison with control values. Besides, they also show that aging induces the greatest decrease in total SOD activity in liver when compared with stomach and pancreas. The diminution in the SOD activity in aging has been well documented.^18
–20 SOD defends against oxygen free radicals by catalyzing the elimination of the superoxide radical, which damages the membrane and biological structures. During oxidative stress, an elevated intracellular Ca²⁺ ion concentration induces the irreversible conversion of xanthine dehydrogenase to xanthine oxidase, which in turn catalyzes the oxidation of xanthine to give a source of superoxide radicals. These reactions and the reduction in SOD activity during aging may lead to overloading of oxygen radicals.²⁸ Above mentioned mechanisms might also be involved in our study to diminish the total SOD activity in the investigated tissues of aged rats.

In our study, one can observe a significant decrease in liver, gastric and pancreatic total SOD activity in rats treated with ethanol when compared with control group. These data also indicate that ethanol, similar to aging, causes the greatest decrease in total SOD activity in liver when compared with stomach and pancreas. These findings are in accordance with well-known fact regarding ethanol as a food component, which influences cellular ROS generation and antioxidant status.^1,8 Furthermore, in our investigation, the most pronounced decrease in total SOD activity was found in liver, stomach and pancreas of ethanol-treated old rats. Having these data in mind, it appears that acute ethanol intoxication exerts synergistic effect on age-induced ROS production in digestive system of old rats. In such circumstances, ethanol is rapidly absorbed from the gastrointestinal tract and about 90% is metabolized in liver. There, ethanol is oxidized into acetaldehyde and next into acetate. These processes are accompanied by free radical generation. Electrophilic free radicals and acetaldehyde readily react with the nucleophile groups of proteins, phospholipids and nucleic acids to produce adducts, some of which have been detected in the tissue of alcoholic patients.²⁹ As a consequence of both aging and ethanol intoxication, conductive changes in the cell membrane properties take place. It means that the cell membrane is not in a position to act as a selective barrier, so impairment of ion permeability, enzyme activity and receptor responsiveness occur. In this regard, it is reported that most of the above mentioned dysfunctions of cell membrane caused by aging and ethanol intake are directly or indirectly linked with oxidative stress.²⁹

Two types of SOD isoenzymes were described in mammalian cells: MnSOD, located in mitochondrial matrix, and CuSOD/ZnSOD, mostly found in cytosol. In the present study, we found that hepatic, gastric and pancreatic CuSOD/ZnSOD activity was decreased in all the experimental groups. Additionally, in our investigation, the greatest decrease in CuSOD/ZnSOD activity was noted in liver of old rats treated with ethanol, suggesting that aging and ethanol induce oxidative stress sinergistically. Therefore, this decrease in CuSOD/ZnSOD activity may be explained by its increased consumption in ROS detoxication. Similar to our results, Schmucker found that aging increases oxidative liver damage due to reduced activity of antioxidant enzymes.²¹ Other studies of oxidative hepatic damage also showed a significant fall in both total and CuSOD/ZnSOD liver activity upon the action of ethanol^{3,6

–10,29} and paracetamol.³⁰ In contrast to CuSOD/ZnSOD, data obtained from the present study show that MnSOD activity was significantly higher in liver and pancreas of ethanol-treated rats in comparison with control values. On the other hand, in each investigated organ of other experimental groups, activity of this enzyme was decreased when compared with control group. According to the previous studies, effects of ethanol on MnSOD activity are inconclusive and depend on dose and route of administration.^31,32 In our study, increase in hepatic and pancreatic MnSOD activity in rats treated with ethanol may be the result of an adaptive response to increase in the ROS production. Since mitochondria are the major source of ROS,³³ it is not surprising that mitochondrial SOD isoenzyme activity is increased after acute ethanol intake. In contrast, in the present study, subsequent decrease in MnSOD activity, which was observed in each investigated organ, indicates the consumption of this enzyme in detoxification of ROS. Similar changes in MnSOD activity were reported in the studies of acute ethanol^6,7,33 and paracetamol intoxications.³⁰

In our study, hepatic and pancreatic nitrites were increased in ethanol-treated rats and control old rats, too. In this regard, a greatest rise in NO _x level was observed in liver and pancreas of old rats treated with ethanol. These findings suggest that reactive nitrogen species are involved in acute ethanol- and aging-induced tissue damage. Besides, in the present study, it appears that acute ethanol intake exerts synergistic effect on age-induced nitrite/nitrate production. Our findings are in correlation with published data, which indicate that aging increases iNOS activity, resulting in high NO level in many tissues.^18,34,35 It was found that ethanol is an inductor of NO synthesis.³⁶ In low concentrations, NO exerts hepatoprotective effects, while in high concentrations, this molecule in the presence of superoxide anion leads to the generation of peroxynitrite, which is known to be a potent oxidant in cells.^33,35 Moreover, it has been shown that ethanol-induced peroxynitrite production in pancreas is in correlation with dysfunction and apoptosis of pancreatic B cells.³⁷

Based on the results of our study, it can be concluded that aging increases sensitivity of hepatic, gastric and pancreatic cells to lipid peroxidation induced by ethanol. Additionally, aging potentiates ethanol-induced impairment of antioxidant defense system in the liver, stomach and pancreas due to a decrease in the activity of total SOD and its both isoenzymes (MnSOD and CuSOD/ZnSOD). Besides, increased nitrite and nitrate production in liver and pancreas of old rats treated with ethanol indicates a possible role of nitrosative stress in age-induced hepatic and pancreatic injury.

Footnotes

Funding

This work was supported by the Ministry of Education and Science of Serbia, Grant no. 175015.

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Influence of aging on ethanol-induced oxidative stress in digestive tract of rats

Abstract

Keywords

Introduction

Materials and methods

Animals

Sample preparation

Biochemical analysis

Chemicals

Statistical analysis

Results

Discussion

Footnotes

Funding

References