Mustafa Nazıroğlu

Protective effects of vitamin E on carbon tetrachloride-induced liver damage in rats.

In this study we investigated whether the increase of hepatic vitamin E content by intraperitoneal administration, influences chronic liver damage induced by carbon tetrachloride (CCl4) in rats. Thirty adult male Wistar rats were divided into three groups. The first group was used as a control and the rats in the second group were administered CCl4 in olive oil subcutaneously. Rats in the third group were administered intraperitoneally vitamin E (dl‐α‐tocopherol acetate, 100 mg kg−1). This administration was performed three times per week for five weeks. Liver samples were used for the determination of vitamin E levels, glutathione peroxidase (GSHPx) activities and histological examination.

Antioxidants and lipid peroxidation status in the blood of patients with psoriasis

The aim of this research was to determine levels in blood of vitamin E, beta carotene, lipid peroxidation as malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) activity in patients with psoriasis. Studies were carried out on 34 patients with moderate and severe psoriases and healthy age-matched controls. Red blood cell (RBC) and plasma samples from healthy and patient subjects were taken. Levels of GSH and the activity of GSH-Px in both plasma and RBC samples were significantly (P<0.001) lower in patients with psoriasis than in controls, whereas beta carotene levels in plasma and MDA levels in RBC samples were significantly (P<0.01, P<0.001) higher in patients with psoriasis than in controls. However, vitamin E and MDA levels in plasma did not differ statistically. Although being far from conclusive, these results provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidants in psoriasis.

Blood plasma levels of lipoperoxides, glutathione peroxidase, beta carotene, vitamin A and E in women with habitual abortion.

The plasma levels of lipoperoxides, glutathione peroxidase (GSH‐Px), reduced glutathione (GSH), beta carotene, vitamin A, E, some plasma biochemical and blood haematological parameters were investigated in 40 women with habitual abortion (HA) and controls. The levels of GSH, vitamin A, E and beta carotene were significantly lower in women with HA than in controls. However, the plasma levels of lipid peroxidation, alkaline phosphatase (ALP), glucose and blood haemoglobin were significantly higher in HA than in controls. In addition, plasma levels of GSH‐Px, AST, ALT, total bilirubin, total protein, albumin, sodium, potassium, calcium and number of white blood cells, red blood cells, platelet and values of packet cell volume showed no significant differences between HA and controls. According to the results of this study, we observed that the levels of lipid peroxidation were increased and plasma levels of vitamin A, E and beta carotene were decreased in HA. The decrease of those antioxidants may play a significant role in women with habitual abortion. Copyright

Inhibitory effects of melatonin on neural lipid peroxidation induced by intracerebroventricularly administered homocysteine

Abstract: Melatonin, the main secretory product of the pineal gland, has been shown to be potentially effective in prevention of numerous types of neurodegenerative disorders in which free radical processes are involved. Homocysteine (Hcy), an independent risk factor for atherosclerosis, undergoes auto‐oxidation and generates reactive oxygen species. The purpose of this study was to test whether intracerebroventricular (ICV) injection of Hcy leads to neural lipid peroxidation and also to investigate the protective effects of melatonin on the brain tissue from oxidative stress of Hcy. Adult male Wistar rats under anaesthesia were injected ICV with Hcy at a dose of 143 μg/kg. Melatonin was administered intraperitoneally to a group of rats for three consecutive days before Hcy injection. The rats were decapitated and brain tissues were removed and hippocampus, cortex and cerebellum were dissected. There was a significant development of oxidative stress as indicated by an increase in malondialdehyde in hippocampus, cortex and cerebellum of rats injected with Hcy, whereas melatonin prevented the elevation of lipid peroxidation. Furthermore, melatonin significantly increased glutathione levels and glutathione peroxidase activity in all brain regions. The present study demonstrates that Hcy, in high levels, may be a causal factor in generation of free radicals in the brain and it may be one of the mechanisms which cause neurodegeneration in elderly people. It also shows that melatonin could potentially be beneficial in prevention of neurodegeneration caused by hyperhomocysteinemia.

Protective role of intraperitoneally administered vitamin E and selenium on the antioxidative defense mechanisms in rats with diabetes induced by streptozotocin.

The aim of this work was to determine the protective effects of intraperitoneally administered vitamin E and selenium (as Na2SeO3, Se) on the lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and vitamin E levels, glutathione peroxidase (GSH-Px), reduced glutathione (GSH) activities in the plasma, red blood cell (RBC), liver, and muscle of rats with streptozotocin-induced diabetes. Fifty adult male Wistar rats were used and all rats were randomly divided into five groups. The first group was used as a control and the second group as a diabetic control. A placebo was given to first and second groups by injection. The third group was intraperitoneally administered with vitamin E (20 mg over 24 h), the fourth group with Se (0.3 mg over 24 h), and the fifth group with vitamin E and Se combination (COM) (20 mg vitamin E + 0.3 mg Se over 24 h). This administration was done for 25 days and the TBARS, vitamin E, GSH-Px, GSH levels in the plasma, RBC, liver, and muscle samples were determined.The vitamin E level in the plasma and liver was significantly (p < 0.05) higher in the control than in the diabetic control group. Also, the TBARS levels in the RBC, liver, and muscle were significantly (p < 0.05) lower in the control than in the diabetic control group. However, GSH-Px and GSH activities in RBC, liver, and muscle were not statistically different between the control and the diabetic control groups. The vitamin E levels in plasma and liver (p < 0.01 and p < 0.001) and GSH-Px activities (p < 0.01, p < 0.001) in RBC were significantly higher in vitamin E, Se, and COM groups than in both control and diabetic control groups. However, the TBARS levels of RBC, muscle, and liver in vitamin E and Se administered groups were significantly (p < 0.05-p < 0.001, respectively) decreased. These results indicate that intraperitoneally administered vitamin E and Se have significant protective effects on the blood, liver, and muscle against oxidative damage of diabetes.

Protective effects of selenium, vitamin C and vitamin E against oxidative stress of cigarette smoke in rats

Cataractous lenses have been found to have an altered distribution of the intracellular ionic environment; the concentrations of potassium and magnesium being decreased and the concentrations of sodium and calcium increased. These changes arise as a result of changes to lens membrane characteristics causing an increase in lens membrane permeability.

ENHANCED TESTICULAR ANTIOXIDANT CAPACITY IN STREPTOZOTOCIN-INDUCED DIABETIC RATS: PROTECTIVE ROLE OF VITAMINS C AND E AND SELENIUM

Diabetes mellitus is associated with diabetic impairment of testicular function, ultimately leading to reduced fertility. Its etiology may involve oxidative damage by reactive oxygen substances, and protection against this damage can be offered by antioxidant supplementation. The aim of this study was to investigate the effects of intraperitoneal administration of vitamin C and E, selenium (Se), and vitamin E plus Se (COM) on concentrations of lipid peroxide (as malondialdehyde; MDA), reduced glutathione (GSH), and vitamin E concentrations and glutathione peroxidase (GSH-Px) activity in the testes of rats with diabetes induced by streptozotocin (STZ). Sixty groups were used (10 animals each) and these animals were initially allocated to two groups: control group and diabetic group. The diabetic group was subdivided into five groups as follows: diabetic control (DC), vitamin E, Se, COM, and vitamin C. Animals in the DC group and vitamin C, vitamin E, Se, and COM groups were made diabetic by the injection of STZ on 4 d after an injection of vitamins C and E, Se, and COM. Those vitamins and Se were also administered for 21 consecutive days. The MDA, vitamin E, GSH levels, and GSH-Px activities in testes were determined.Although the vitamin E concentration was higher in the control than in the DC group, the MDA levels were found to be lower in the control than in the DC group. The MDA levels in the testes samples of vitamin C, vitamin E, Se, and COM groups were lower than the DC group. However, GSH-Px activity and GSH levels in the testes were not significantly different between the control and DC groups. Vitamin E concentrations in the vitamin C, vitamin E, Se, and COM groups and GSH levels and GSH-Px activities in the Se, COM, and vitamin C groups were higher than either the control or DC group.The results indicate that reactive oxygen substances may be involved in possible testicular complications in diabetes of rats. Administration of vitamins C and E and Se reduced the testicular lipid peroxidation; these vitamins and Se had significant protective effects on testes of rats against oxidative damage in diabetes.

Antioxidants and lipid peroxidation status in the blood of patients with alopecia.

The aim of this research was to determine levels in blood of vitamin E, beta‐carotene, lipid peroxidation as thiobarbituric‐acid reactive substances (TBARS) and reduced glutathione (GSH) and activity of glutathione peroxidase (GSH‐Px) in patients with alopecia. Studies were carried out on 37 patients with alopecia and 34 healthy age‐matched controls. Red blood cell (RBC) and plasma samples from healthy and patient subjects were taken. Beta‐cartotene levels (P<0·001) in plasma and levels of GSH (P>0·05) and the activity of GSH‐Px (P<0·05, P<0·01) in both plasma and RBC samples were significantly lower in patients with alopecia than in controls, whereas TBARS levels in plasma (P<0·05) and RBC (P<0·001) samples were significantly higher in patients with alopecia than in controls. However, vitamin E levels in plasma did not differ statistically. Although being far from conclusive, these results provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidants in alopecia. Copyright

The levels of some antioxidant vitamins, glutathione peroxidase and lipoperoxidase during the anaesthesia of dogs.

The aim of this investigation was to determine serum levels of vitamin A, E, beta carotene, glutathione peroxidase (GSHPx), lipid peroxidation (MDA) and biochemical and haematological parameters during enflurane anaesthetised dogs. Ten kangal dogs were used and all animals were anaesthetised with enflurane for two hours and blood samples were taken before and 30, 120 minutes, 24 hours and 7 days during the anaesthesia. Vitamin E and beta carotene content were significantly (p<0·05 and p<0·01) higher before anaesthesia than after whereas serum GSHPx activity was not statistically different. However, serum levels of vitamin A and MDA were significantly (p<0·05) increased during the anaesthesia.

Protective role of intraperitoneally administered vitamin E and selenium in rats anesthetized with enflurane

The aim of this investigation was to determine levels of liver vitamins A and E and blood biochemical and hematological parameters in the enflurane anesthesia of rats. Fifty adult male Wistar rats were used in this study. All rats were randomly divided into five groups. The first and second groups were used as the control and anesthesia control groups, respectively, and only the placebo was intraperitoneally injected. The third group was intraperitoneally administered with vitamin E (dl/-α-tocopheryl acetate, 100 mg/kg body weight), the fourth group with Se (Na2SeO3 1.5 mg/kg body weight), and the fifth group with vitamin E and Se (dl-α-tocopheryl acetate, 100 mg/kg body weight + Na2SeO3 1.5 mg/kg body weight). This administration was done for three times with overday intervals and the second, third, forth, and fifth group rats were taken to enflurane anesthetise for 2 h.The liver vitamin E level was slightly lower in the anesthesia control group than in control group. However, the liver vitamin E content was significantly (p < 0.05 andp < 0.01) increased in vitamin E, Se, and combination groups, whereas the vitamin A level in liver was not statistically different.In general, plasma levels of alanine aminotransferase, creatin kinase, total bilirubin, urea, red blood cell counts, packet cell volume, and hemoglobulin values were significantly (p < 0.05 andp < 0.001) increased during the anesthesia and returned to near control values after the vitamin E plus selenium injection. However, administration of vitamin E had less effect on the hematological and biochemical parameters compared to that of selenium and their combination with vitamin E. However, the white blood cell count and levels of alkaline phosphatase, aspartate aminotransferase, total cholesterol, triglycerides, total protein, and creatinine were not statistically influenced by the anesthesia.In conclusion, we observed that plasma levels of some enzymes and metabolites were significantly increased in the enflurane anesthesia of rats, whereas the liver vitamin E levels were slightly decreased. Therefore, we observed that vitamin E and selenium have a protective effect against anesthesia complication, but the effect of selenium appears to be much greater than the vitamin E.