Mine İnal

Antioxidant enzyme activities and malondialdehyde levels related to aging.

BACKGROUND Free oxygen radicals have been proposed as important causative agents of aging. We have evaluated age-related changes in antioxidant enzyme activities and lipid peroxidation. METHODS We measured erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and plasma malondialdehyde (MDA) levels. One hundred and seventy six healthy subjects were divided into five groups: Group 1 (n = 25; 0.2-1 year-old), Group 2 (n = 28; 2-11 years), Group 3 (n = 23: 12-24 years), Group 4 (n = 40; 25-40 years), Group 5 (n = 60: 41-69 years). RESULTS SOD activities in Group 5 were significantly lower than in the other groups (P < 0.001). GPx and CAT activities and MDA levels in Group 5 were significantly higher than the other groups (P < 0.001, respectively). CAT activity in Group 4 was significantly higher than group 1 and group 2 (respectively, P < 0.001), and in group 3 was high compared to Group 2 (P < 0.001). There were negative correlations between SOD activities and age (P < 0.001). Conversely, there were positive correlations between CAT, GPx and MDA levels and age (P < 0.001). CAT activities of women in Group 2 were found to be high compared to the men (P < 0.05). MDA levels of women in Group 5 were higher than in the male groups (P < 0.001). CONCLUSIONS We found age-related differences in erythrocyte antioxidant enzyme activities. Furthermore, peroxidative injury is raised in the aging process.

Effect of aerobic and anaerobic metabolism on free radical generation swimmers

PURPOSE In this study, changes in antioxidant systems due to free radicals were investigated in short distance (100-m) and long-distance (800-m) swimmers, within whom the anaerobic and aerobic metabolisms dominate, respectively. METHODS For this study, swimmers aged between 15 and -21 yr swam 800 m (N = 10) and 100 m (N = 9). Venous blood samples were taken before swimming, and at 1-, 20-, and 40-min intervals after swimming. Lactate, catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) levels were determined in the blood samples. RESULTS The increase of lactate levels was statistically significant in the swimmers, both after the 100- and 800-m distances as compared with the preswimming levels (P < 0.001, P < 0.001). Catalase activity was increased in the first minute postswimming as compared with preswimming levels. Catalase activity then decreased at the 20- and 40-min intervals as compared with the 1-min postswimming interval, at both 100- and 800-m distances (P < 0.01, P < 0.001). GPx activity was also increased in the first minute after swimming as compared with preswimming levels. GPx activity then decreased at the 20- and 40-min intervals when compared with the 1-min postswimming level. This occurred in both 100- and 800-m swimmers (P < 0.001, P < 0.001). GSH activity was decreased in the first minute after swimming, compared with the preswimming levels. GSH activity then increased at the 20- and 40-min postswimming intervals, as compared with the first-minute level. Again, this occurred in both the 100- and 800-m swimmers (P < 0.001, P < 0.01). CONCLUSION We concluded that both long-distance and particularly short-distance (100-m) swimming increased the activities of antioxidant defense enzymes.

The effect of nitric oxide on ischemia–reperfusion injury in rat liver

A dual role for nitric oxide (NO) in ischemia-reperfusion (I/R) injury is still controversial. This study aims to investigate the role of NO in rat hepatic reperfusion injury. Ischemia was induced by total occlusion of hepatic artery and portal vein for 30 min, then the tissue was reperfused for 30 min. The animals in the L-NAME group (n=10) received N(G)nitro-L-arginine methyl ester (L-NAME) (15 mg/kg) intraperitoneally 60 min before ischemia. The ischemia group (n=10) was given an equal volume of saline solution. The control group comprised eight healthy rats which were not exposed to ischemia or reperfusion. An indicator of hepatic injury, plasma alanine amino transferase (ALT) enzyme activities, were increased in the L-NAME group as compared with the ischemia group (p<0.001). The level of serum nitrite, an index of NO production, and hepatic reduced glutathione (GSH) concentration were lower in the L-NAME group than in the ischemia group (p<0.001, p<0.01, respectively). Hepatic levels of malondialdehyde (MDA) and conjugated dienes (CD) were significantly increased in the L-NAME group as compared to the ischemia group (p<0.05, p<0.001, respectively). Our results confirm that L-NAME, an inhibitor of the enzyme NO synthase, increased the lipid peroxidation and possibly tissue injury, due to the inhibition of cytoprotective effects of NO in a rat hepatic I/R model.

Antioxidant status and lipid peroxidation in hemodialysis patients undergoing erythropoietin and erythropoietin-vitamin E combined therapy.

In this study, plasma and red blood cell (RBC) antioxidant status and plasma lipid peroxidation were investigated in 46 hemodialysis patients. In addition, the effect of erythropoietin (EPO) and EPO-vitamin E combination therapy on plasma and RBC antioxidant status, and plasma lipid peroxidation were examined. There were 10 healthy subjects in the control group and 10 hemodialysis patients in the untreated group. The third group included 36 hemodialysis patients that were given EPO (100 U/kg) for 3 months, 3 times per week. The fourth group included 36 hemodialysis-patients from the EPO group that were given EPO at a 50% decreased dose + vitamin E (300 mg/day) for 3 months. MDA levels in the untreated group, the EPO group and the EPO + vitamin E groups were found to be higher than the control group (p < 0.001, in both). Furthermore, MDA levels in both of the treatment groups were lower when compared to the untreated group (p < 0.001, in both). Plasma vitamin E levels in the untreated, the EPO group and EPO + vitamin E groups were lower than the control group (p < 0. 001). In contrast, plasma vitamin E levels in the treatment groups were higher in comparison with the control group (p < 0.05). SOD activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001). SOD activities in the treatment groups were higher than the control group (p<0.001). The SOD activities in the EPO+vitamin E group increased when compared to the EPO group (p < 0.001). CAT activities in the untreated, the EPO group and the EPO + vitamin E groups were found to be lower than the control group (p < 0.001 in untreated and EPO groups, p <0.01 in EPO+ vitamin E group). CAT activities in EPO and EPO+ vitamin E groups were increased when compared to the untreated group (p < 0.01). In conclusion, our findings have shown that antioxidant status decreased and lipid peroxidation increased in hemodialysis patients. EPO has an antioxidant effect on the RBC and plasma antioxidant status, and plasma lipid peroxidation. These effects were moderately increased by the combination of vitamin E and EPO.

Effects of postmenopausal hormone replacement and α-tocopherol on the lipid profiles and antioxidant status

Sixty-six postmenopausal women were randomly divided into three groups. The first group (n = 22) received transdermal oestradiol (0.05 g/day) for six months. Transdermal oestradiol was given during three weeks but was not given in the following week of each month during six months. In addition to the first groups therapy, medroxyprogesterone acetate (MPA; 10 mg/day, per orally) was administered to the second group (n = 22) for the last ten days. Vitamin E (600 mg/day, per orally) was given to the third group (n = 22) in addition to the first and second group therapy every day during six months. Total cholesterol, high density lipoprotein (HDL), very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels of the three groups were measured at the beginning and at the end of therapy. In the transdermal oestradiol and transdermal oestradiol + MPA groups, post-treatment serum total, VLDL and LDL cholesterol levels decreased (P < 0.05) whereas HDL cholesterol level increased (P < 0.05). No significant difference was found in the levels of MDA, SOD and GSH-Px. In the third group, pre-treatment levels of total (P < 0.05), VLDL (P < 0.05), LDL cholesterol (P < 0.01) and MDA (P < 0.05) were high compared to post-treatment. Inversely, HDL cholesterol (P < 0.05) and vitamin E (P < 0.01) levels increased after the treatment. However, there was no significant difference in the levels of SOD and GSH-Px. In conclusion, in the post-menopausal period, because of the positive changes after hormone replacement plus vitamin E therapy, we suggest that hormone replacement and vitamin E combined therapy is effective in prevention of cardiovascular diseases.

Lazaroid attenuates edema by stabilizing ATPase in the traumatized rat brain

OBJECTIVE The aim of the present study was to determine the potential therapeutic value of the lazaroid U-83836E on blood brain barrier (BBB) breakdown and edema with respect to the changes in the synaptosomal Na+/K+ and Mg(2+)/Ca(2+)-adenosinetriphosphatase (ATPase) activities, tissue malondialdehyde levels and the neuronal viability in the rat brain subjected to cerebral trauma. METHODS Traumatic brain injury (TBI) was introduced by applying a 75 gm. cm force to the right parietal cortex using the weight-drop method. The first set of animals was used for determining time course changes of the synaptosomal Na+/K+ and Mg(2+)/Ca(2+)-ATPase and the malondialdehyde levels and were sacrificed 2, 6 and 24h after lesion production. A group of the animals was treated with U-83836E proir to TBI and sacrificed 24h after cerebral injury. A second set of animals was used for evaluating the alterations in BBB disruption and tissue water content and were sacrificed 2, 6 and 24h after lesion production. Two groups of animals were treated with U-83836E and sacrificed after 2 and 24h following TBI. U-83836E was given intraperitoneally thirty minutes before trauma at a dose of 10 mg/kg. Neuronal necrosis was also evaluated in the groups of U-83836E and physiological saline-treated animals. RESULTS Extravasation of Evans blue into the traumatized hemisphere was maximum at 2h (p<0.001) and returned close to the control levels at 24h after TBI (p>0.05). Edema had developed progressively over time and reached the maximum degree of 2.1% (p<0.001) at 24h. U-83836E showed no effect on the BBB breakdown and the tissue water content at 2h and still had no effect on the BBB breakdown after 24h following the trauma (p>0.05), although it reduced edema after 24h (p<0.01). The losses of Na+/K+ and Mg(2+)/Ca(2+)-ATPase activities were found as 39.5% (p<0.001) and 29.4% (p<0.01) of the control value, respectively, and remained at the decreased levels throughout the experiment. Malondialdehyde level continued to increase over time reaching up to 209% (p<0.001) of the control value 24h after TBI. Both ATPase activities were improved to near control values (p>.05) by the effect of U-83836E. U-83836E inhibited the increase of lipid peroxidation (p<0.001) and also salvaged neuronal necrosis (p<0.05). CONCLUSION U-83836E given prophylactically after cerebral trauma appears to reduce edema, possibly by inhibiting increases in lipid peroxidation and by stabilizing ATPase. Further studies are recommended to verify the similar effects of the brain penetrating lazaroids when they are given after trauma.

The role of free radicals in p-aminophenol-induced nephrotoxicity: does reduced glutathione have a protective effect?

The role of free radicals in p-aminophenol (PAP)-induced nephrotoxicity and effects of reduced glutathione (GSH) were investigated. We injected PAP in one group of rats and PAP plus GSH in a second group. All parameters were measured in the renal tissue. Superoxide dismutase (SOD) activity in the PAP + GSH group (7.1 +/- 0.36 U/mg protein) was found to be significantly higher than in the control group (4.9 +/- 0.13) (P < 0.001). Catalase (CAT) was found to be significantly low in both groups (P < 0.001 in the PAP group (13.48 +/- 0.85 U/mg protein), P < 0.01 in the PAP + GSH group (18.75 +/- 1.17) as compared to the control group (41.03 +/- 0.93)). Glutathione peroxidase (GPx) in the PAP and PAP + GSH groups was found to be significantly high (P < 0.01 in the PAP group (5.32 +/- 0.033 U/mg protein), P < 0.001 in the PAP + GSH group (6.48 +/- 0.1)) as compared to the control group (2.93 +/- 0.093)). Similarly, glutathione reductase (GSSGR) in the PAP (0.023 +/- 0.002 U/mg protein), and PAP + GSH (0.025 +/- 0.001) groups was found to be significantly high as compared to the control group (0.014 +/- 0.001) (P < 0.001). GSH in the PAP (161.93 +/- 8.3 mg/mg protein) and PAP + GSH (170.7 +/- 4.51) groups were found to be significantly higher than the control group (104.91 +/- 3.0) (P < 0.001). Malondialdehyte (MDA) in the PAP (11.2 +/- 0.62 nmol/mg protein) and PAP + GSH (9.72 +/- 0.46) groups was found to be significantly higher than in the control group (5.54 +/- 0.51)(P < 0.001). Free radicals might have a major role in the PAP-induced nephrotoxicity. GSH increased nephrotoxicity.

Effects of intrarectal and intraperitoneal N(G)-nitro-L-arginine methyl ester treatment in 2,4,6-trinitrobenzenesulfonic acid induced colitis in rats.

Inflammatory bowel disease (IBD) has been associated with an increased generation of nitric oxide (NO). Different authors have shown that NO in IBD can be either harmful or protective. The aim of this study was to investigate the efficiency of intrarectal (i.r.) and intraperitoneal (i.p.) application of N(G)-nitro-L-arginine methyl ester (L-NAME), a non-specific nitric oxide synthase inhibitor, in experimental acute colitis in the rats. Acute colitis was induced in rats by 2,4,6-trinitrobenzenesulfonic acid (TNBS) and ethanol. Twenty-eight rats were divided into four groups. L-NAME (50 mg/kg/day) was administered i.p. (Group 1) and i.r. (Group 2) for 7 days following the day when colitis was induced. Group 3 rats were not given any treatment after induction of colitis. Control group rats were given saline solution i.r. instead of TNBS. The presence of hyperemia, inflammation and ulcer was evaluated to score of macroscopic morphologic damage. The severity of colitis was assessed by microscopic criteria including ulceration, mucus cell depletion, crypt abscesses, inflammatory cysts, mucosal atrophy, edema, inflammatory cell infiltration, and vascular dilatation. Rectal tissue myeloperoxidase (MPO) activity and serum-rectal tissue nitrite levels were measured. Serum and rectal tissue nitrite levels increased in Group 3 rats. Both i.p. and i.r. L-NAME treatment significantly reduced serum and rectal tissue nitrite levels, but no effect on MPO activity and histologic damage score was observed. Under the present conditions we concluded i.r. and i.p. L-NAME treatment, applied at the dosage of 50 mg/kg/day, does not have any protective effect on the colonic injury.

Effect of boric acid on oxidative stress in rats with fetal alcohol syndrome

To the best of our knowledge, this is the first study concerning the effect of boric acid (BA) administration on fetal alcohol syndrome (FAS). In this study, the aim was to investigate prenatal alcohol-induced oxidative stress on the cerebral cortex of newborn rat pups and assess the protective and beneficial effects of BA supplementation on rats with FAS. Pregnant rats were divided into three groups, namely the control, alcohol and alcohol + boric acid groups. As markers of alcohol-induced oxidative stress in the cerebral cortex of the newborn pups, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels were measured. Although the MDA levels in the alcohol group were significantly increased compared with those in the control group (P<0.05), the MDA level in the alcohol + boric acid group was shown to be significantly decreased compared with that in the alcohol group (P<0.01). The CAT activity of the alcohol + boric acid group was significantly higher than that in the alcohol group (P<0.05). The GPx activity in the alcohol group was decreased compared with that in the control group (P<0.05). These results demonstrate that alcohol is capable of triggering damage to membranes of the cerebral cortex of rat pups and BA could be influential in antioxidant mechanisms against oxidative stress resulting from prenatal alcohol exposure.

Betaine (Trimethylglycine) as a nutritional agent prevents oxidative stress after chronic ethanol consumption in pancreatic tissue of rats

In this study, we investigated the free radical-mediated cytotoxic effects of chronic ethanol consumption on the pancreatic tissue and a possible cytoprotective effect of betaine as a methyl donor and an important participant in the methionine cycle. Twenty-four male Wistar rats were divided into control, ethanol, and ethanol+betaine groups. Prior to sacrifice, all groups were fed 60 mL/diet per day for two months. Rats in the ethanol group were fed with ethanol 8 g/kg/day. The ethanol+betaine groups were fed ethanol plus betaine (0.5 % w/v). Malondialdehyde levels and adenosine deaminase, superoxide dismutase, and xanthine oxidase activities were determined in pancreatic tissues of rats. Compared to control group, MDA levels increased significantly in the ethanol group (p<0.05). MDA levels in the ethanol+betaine group were significantly decreased compared to the ethanol group (p<0.05). ADA activity in the ethanol+betaine group decreased significantly when compared to the ethanol group (p<0.05). XO activities in ethanol-fed rats were decreased significantly compared to the control group (p<0.05). XO activity in the betaine group was increased significantly (p<0.05) compared to the ethanol group. SOD activity in the ethanol group decreased significantly compared to control group (p<0.001). SOD activity in the ethanol+betaine group decreased significantly (p<0.05) compared to the control group. We think that betaine, as a nutritional methylating agent, may be effective against ethanol-mediated oxidative stress in pancreatic tissue.