Protective effects of vitamin E against atrazine-induced genotoxicity in rats

Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) is one of the most commonly used herbicides to control grasses and weeds. The widespread contamination and persistence of atrazine residues in the environment has resulted in human exposure. Vitamin E is a primary antioxidant that plays an important role in protecting cells against toxicity by inactivating free radicals generated following pesticides exposure. The present study was undertaken to investigate the protective effect of vitamin E against atrazine-induced genotoxicity. Three different methods: gel electrophoresis, comet assay and micronucleus test were used to assess the atrazine-induced genotoxicity and to evaluate the protective effects of vitamin E. Atrazine was administered to male rats at a dose of 300 mg/kg body weight for a period of 7, 14 and 21 days. There was a significant increase (P<0.001) in tail length of comets from blood and liver cells treated with atrazine as compared to controls. Co-administration of vitamin E (100 mg/kg body weight) along with atrazine resulted in decrease in tail length of comets as compared to the group treated with atrazine alone. Micronucleus assay revealed a significant increase (P<0.001) in the frequency of micronucleated cells (MNCs) following atrazine administration. In the animals administrated vitamin E along with atrazine there was a significant decrease in percentage of micronuclei as compared to atrazine treated rats. The increase in frequency of micronuclei in liver cells and tail length of comets confirm genotoxicity induced by atrazine in blood and liver cells. In addition, the findings clearly demonstrate protective effect of vitamin E in attenuating atrazine-induced DNA damage.     

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 (CCl(4)) 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 CCl(4) in olive oil subcutaneously. Rats in the third group were administered intraperitoneally vitamin E (dl-alpha-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. Serum levels of alanine aminotransferase, lactate dehydrogenase, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyltranspeptidase, total and conjugated bilirubin were significantly (p<0.05, p<0.01, p<0.001) higher in animals treated with CCl(4) than in the controls and had returned to normal values by the administration of vitamin E + CCl(4 ). Liver vitamin E levels were significantly (p<0.05) lower in the CCl(4) group than in the control group. However, the liver vitamin E content was significantly (p<0.01, p<0.001) increased in the vitamin E + CCl(4) injected group. On the other hand, liver GSHPx activity was not statistically different among the groups. On histological examination, vitamin E administered animals showed incomplete, but significant, prevention of liver necrosis and cirrhosis induced by CCl(4 ). these data indicate that intraperitoneally administered vitamin E has protective effects against CCl(4)-induced chronic liver damage and cirrhosis as evidenced by biochemical data and conventional histological examination.     

Estrogen administration, postexercise tissue oxidative stress and vitamin C status in male rats

Estrogen can putatively act as an antioxidant and protect tissues from exercise-induced oxidative stress. To test the in vivo efficacy of estrogen, the effects of 2 weeks of daily estrogen (40 microg x kg(-1) body weight beta-estradiol 3-benzoate) injection on indices of immediate postexercise oxidative stress and antioxidant status were determined in adult male rats, with and without 8 weeks of prior dietary vitamin E deprivation. The treadmill running protocol (60 min at 21 m x min(-1), 12% grade) induced significant oxidative stress as indicated by muscle glutathione status. Estrogen administration had little effect on postexercise tissue glutathione status, superoxide dismutase and glutathione peroxidase activity, and vitamin E levels. Estrogen administration induced significant reductions in muscle, liver, and heart vitamin C concentrations following exercise, as well as in unexercised male rats. Tissue vitamin C loss was not directly mediated through liver glycogen or glutathione status. Thus, estrogen administration generally did not appear to influence postexercise tissue indices of oxidative stress or antioxidant status and may have contributed to a decline in overall antioxidant protection by inducing losses in tissue vitamin C content.     

Antistress effects of vitamin E and dimethylsulfoxide during their combined administration in low doses

Low doses of vitamin E (5 mg/kg body weight) and dimethyl sulfoxide (50 mg/kg) given simultaneously orally to albino rats prevented the disturbances of the behaviour and vegetative functions induced by chronic emotional painful stress. The adaptive effect of vitamin E or dimethyl sulfoxide given alone was much lower or altogether absent. The antioxidant combination used decreased the intensity of lipid peroxidation in the brain and blood serum as well as cholesterol content in brain lipids and activated brain superoxide dismutase and nonenzymatic superoxide scavenging activity of the serum. The results obtained suggest that the combination of vitamin E with dimethyl sulfoxide may be used for the treatment of pathological conditions accompanied by lipid peroxidation syndrome.     

Plasma prolactin levels in parental male rats: effects of increased pup stimuli

The effects of pup exposure on plasma prolactin (PRL) levels were measured in unrestrained, steriod-primed, orchidectomized parental rats. Castrated adult male rats were treated with estradiol and progesterone for 3 weeks and then exposed to rat young until parental behavior was induced. Blood samples were then collected from parental males in both the presence and the absence of pups. Samples were obtained through the use of indwelling cannulas connected via polyethylene tubing to syringes located outside each subject's cage. Despite the intense pup stimulation provided by exposure to nine rat pups, acute rises in plasma PRL levels were not observed in these unrestrained parental male rats. Parental male rats, therefore, do not appear to have the capacity to secrete prolactin in response to acute exposure to young.     

Serum vitamin A and vitamin E concentrations after parenteral vitamin A administration in sheep

Twenty primiparous dairy sheep of the Mytilene breed, which were fed with a ration deficient in vitamin A and carotenes, were divided into 2 groups of 10 animals each after a 2-month adaptation period. The animals of group A were administered vitamin A palmitate by intramuscular injection (3500 IU/kg bodyweight), while the animals of group B were used as controls and received only the vehicle of the preparation without vitamin A. Serum vitamin A concentrations increased significantly in the animals of group A compared to the animals of group B (P < 0.01) from the first 24 h post-injection and remained significantly high for 8 days, and at 10 days post-injection they reached the pre-injection levels. The serum vitamin E concentration declined significantly (P < 0.05) in the animals of group A compared to the animals of group B for 8 days, when they reached the pre-injection levels. No changes in serum vitamins A and E levels in the animals of the 2 groups were observed 20 days after the injection of vitamin A.     

Pinealectomy and melatonin administration in rats: their effects on plasma leptin levels and relationship with zinc

The aim of this study was to examine effects of pinealectomy and melatonin administration plasma leptin levels and its relationship with zinc in rats. The study was conducted on 40 adult male Sprague-Dawley rats. They were divided into four groups each containing 10 animals. Group 1 served as control. Group 2 was pinealectomized group. Animals in Group 3 were pinealectomized and injected with melatonin (3 mg/kg/day, ip). Group 4 received melatonin alone (3 mg/kg/day, ip). At the end of the experiments, all animals were decapitated and trunk blood collected. Plasma leptin and zinc levels were determined by radioimmunoassay and Atomic Absorption Spectrophotometer methods, respectively. Although mean weights of the animals at the beginning were not significantly different among the groups, the mean weight of the pinealectomized group was found to be significantly lower than all other groups at the end of a six-month period (p < 0.01). Plasma leptin and zinc levels were the highest in melatonin-administered group (group 4; p < 0.01). The lowest plasma leptin and zinc levels were obtained in the pinealectomized group (group 2; p < 0.01). Changes in these two parameters were not statistically significant in groups 1 and 3. Our findings indicate that pinealectomy results in a decrease in leptin and zinc levels in rats, and that melatonin administration to pinealectomized rats prevents the decrease in the these parameters. In addition, long-term administration of melatonin to rats leads to an increase in both leptin and zinc concentrations.     

Comparative effects of melatonin and vitamin E in restoring aortic relaxation in pancreatectomized rats

In a previous study we reported the efficacy of melatonin to restore the decreased relaxation response to acetylcholine (ACh) or to sodium nitroprusside (SNP) in aortic rings of rats turned hyperglycemic by subtotal pancreatectomy. The effect was amplified by pre-incubation in a high (44 mmol/l) glucose solution, a situation that resulted in oxidative stress. We hereby compare the effect of another antioxidant, vitamin E, with that of melatonin on ACh response in intact aortic rings or on SNP response in endothelium-denuded aortic rings obtained from pancreatectomized or sham-operated rats. Dose-response curves to ACh or SNP were performed in the presence or absence of melatonin or vitamin E (10-5 mol/1) in 10 or 44 mmol/1 glucose medium. Melatonin was more effective than vitamin E in restoring ACh- or SNP-induced relaxation of aortic rings in a high glucose medium. The differences between the two antioxidants may rely on the ability of melatonin to diffuse readily into intracellular compartments.     

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. In this study flame atomic absorption spectroscopy (AAS) was used for calcium, magnesium, iron and zinc determination, and flame atomic emission spectroscopy (AES) was used for sodium and potassium contents in normal and cigarette smoke-exposed rat lenses. The methods are sensitive enough to detect quantitatively all six cations in a single rat lenses. In this work, six elements, including Ca2+, K+, Na+, Zn2+, Fe2+ and Mg2+ in experimental rat eye lenses and normal transparent lenses were determined. It was found that the concentrations of Ca2+, Na+, Zn2+, and Fe2+ were increased dramatically while K+ and Mg2+ decreased in smoke-exposed rat lenses when compared to the control rat lenses. There were no significant changes between 'smoked' rats supplied with vitamin C and control groups. A positive correlation was found also in the other two groups of 'cigarette smoked' animals supplemented with selenium plus vitamin E and selenium when compared with 'cigarette smoked' without any supplements. These data provide support for the hypothesis that cigarette smoking increases the risk of cataract formation. We investigated whether vitamin C is the most important antioxidant in the body. The roles of diet with optimum amounts of antioxidant vitamins C and vitamin E and the antioxidant mineral selenium are discussed.     

Beneficial effects of enrichment of chicken meat with n-3 polyunsaturated fatty acids,vitamin E and selenium on health parameters: a study on male rats

Consumption of chicken meat enriched with bioactive compounds such as n-3 polyunsaturated fatty acids (PUFAn-3), vitamin E (vE) and selenium (Se) can help prevent many diseases and can be used to deliver those substances to humans. This might be of importance as chicken meat consumption is increasing worldwide. The effects of enriching chicken meat with PUFAn-3, vE and Se through dietary interventions were studied in rats. Four groups of Ross 308 female broilers from day 22 to day 35 of age were fed control diet (L) that contained lard and 80 mg vE and 0.3 mg Se/kg, or diets that contained rape seeds and fish oil with the same level of Se and vE as in the control diet, the same level of Se as in the control and 150 mg vE/kg, or 150 mg of vE and 0.7 mg Se/kg. Broiler carcasses were boiled, deboned, lyophilized and pooled by group. Boiled edible components of chicken carcass (BECC) were included (240 g/kg) in the diets fed to four groups of ten 10-week-old Wistar male rats for 8 weeks. Inclusion of BECCs modulated dietary fatty acid profile in the rat diets. Feeding these diets did not influence parameters related to growth or relative weights of internal organs in the rats. Feeding BECCs with lower PUFAn-6/n-3 decreased the n-6/n-3 ratio in the rat brain and liver, and increased the proportion of docosahexaenoic acid in the brain lipids. Liver cholesterol level was similar among the experimental groups, whereas the concentration of vE in the liver of rats fed BECC with increased vE levels was higher than that in the rats fed BECC with the basal vE level. Haematological and biochemical parameters in blood were within the normal range for rats, but a few rats showed a tendency towards increased levels because of the higher vE and Se level. The health-promoting effect of feeding rats PUFAn-3 enriched BECC was more pronounced when an increased dietary level of vE was used, but the increased level of Se did not provide the rats with additional benefits. Thus, the findings indicate that BECC enriched with PUFAn-3 and vE by a dietary intervention is a functional food with great potential of implementation.     

Protective effects of GSH,vitamin E,and selenium on lipid peroxidation in cadmium-fed rats

Increased intake of Cd results in its retention and in peroxidative damage in soft tissues. Coadministration of antioxidants, viz., glutathione (GSH), α-tocopherol, and Se, restricted the uptake and distribution of Cd in liver and kidney of rats. Moreover, no rise in malondialdehyde was recorded. Although possible antioxidative mechanisms manifested by GSH, α-tocopherol, and Se have been discussed, it is hypothesized that GSH functions as a Cd chelator. Glutathione yielded favorable effects in comparison to Se and α-tocopherol.     

In vivo metabolism of 3H-testosterone in adult male rats: effects of estrogen administration.

The metabolism of testosterone (T) was studied in normal adult male rats using a constant infusion of trace amounts of the 3H-steroid into a tail vein for 3 h in order to attain a state of equilibrium. Samples of plasma, liver, kidney, prostate, seminal vesicles and muscle were analysed for 3H-testosterone, 3H-5alpha-dihydrotestosterone (5alphaDHT) and 3H-5alpha-androstanediol (Adiol). When compared to the 3H-T level in plasma there were high levels of 3H-T in kidney and of 3H-5alphaDHT in prostate and seminal vesicles. Intraperitoneal estradiol valerate administration (100 mug/day) for 4 days decreased and 3H-5alphaDHT levels in the prostate and seminal vesicles. The estrogen administration increased the T metabolic clearance rate from 17.5 1/24 h/100 g body wt to 22.6 1/24 h/100 g body wt.     

Influence of vitamin E on the levels of fatty acids and MDA in some tissues of diabetic rats

This study was performed to determine whether vitamin E supplementation in streptozotocin-induced diabetic rats treated with insulin could affect the levels of fatty acid composition and malondialdehyde (MDA) of brain, liver and muscle tissues. Thirty Wistar albino rats were used during the experiments. They were randomly divided into three groups, each consisting of six individuals. The first group was diabetic, the second was control, and the third was diabetic but fed vitamin E. The level of stearic acid in brain tissues decreased (p<0.05) in the second and the third groups as compared to the first group. The percentage of arachidonic and polyunsaturated fatty acids slightly decreased (p<0.05) in the diabetic group in comparison to the second and third groups. The proportion of docosahexaenoic acid significantly increased (p<0.01) in the second and third groups in contrast to the first group. The level of docosatrienoic was slightly higher (p<0.05) in the third group than in other groups. In the liver tissues, the proportion of stearic, oleic and total monounsaturated fatty acids was slightly higher (p<0.05) in the first group than in the other groups. The level of arachidonic, docosahexaenoic, unsaturated and total polyunsaturated fatty acid slightly increased (p<0.05) in the second and third groups as compared to the first group. The level of myristic and stearic acids in muscle tissue slightly increased (p<0.05) in the first group as compared to the second and third groups. The proportion of arachidonic, docosahexaenoic and unsaturated fatty acids slightly increased (p<0.05) in the second and third groups relative to the first group. The amount of MDA was slightly higher in the diabetic group than in the other groups in all tissues. The results indicate that vitamin E supplementation, in experimental diabetes could play a role in controlling the oxidative status and altered fatty acid metabolism in tissues, thereby maintaining favourable fatty acid distribution in the tissues affected by diabetic complications.     

Effect of vitamin E on adjuvant arthritis in rats

Adjuvant arthritis was induced in rats fed a diet deficient in or supplemented with vitamin E, and its severity was scored according to the macroscopic findings of their legs, tails, and ears. The average score so obtained was higher in the vitamin E-deficient diet group than in the group of rats supplemented with vitamin E. Whereas the A/G ratio remained depressed in vitamin E-deficient rats, rats on a vitamin E-supplemented diet showed a fast recovery from A/G-ratio depression. The serum levels of beta-glucuronidase and acid phosphatase were elevated after administration of an adjuvant. The serum levels of these lysosomal enzymes showed a remarkable increase in rats fed a vitamin E-deficient diet, while the elevation in lysosomal enzyme levels in rats fed a vitamin E-supplemented diet was inhibited. The levels of thiobarbituric acid (TBA) reactants in the synovia were elevated at 2 weeks after exposure to the adjuvant and were decreased thereafter. In rats maintained on a diet supplemented with vitamin E, on the other hand, the increase in synovial level of TBA reactive substances was inhibited. These observations suggest that the aggravation of adjuvant arthritis may be associated with lipid peroxidation and that antioxidants, such as vitamin E, may be beneficial for arthritis.