Antioxidant defense of rat organism at long-term per oral injection of taurine

Abstract

Aim of this work was to study the activity of antioxidant defense enzymatic link, glucose-6-phosphate dehydrogenase activity and content of TBA-active products at long term per oral injection of taurine. Male Wistar rats (4.5 months old and with body weight 190–220 g) were used in the experiments. Animals were randomly divided into three groups: one control group and two experimental groups. During 28 days period, animals were daily injected in esophagus: control group – drinking water, experimental group I and II – solution of taurine (40 and 100 mg/kg of body weight, respectively). On the 29 th day, the animals were decapitated under light chloroform anesthesia, and liver, brain, testes and thigh muscle were extirpated. The tissues were homogenized and then centrifuged for 15 min at 1,000 g. In supernatant, the activities of superoxide dismutase, glutathione peroxidase, catalase and glucose-6-phosphate dehydrogenase, and content of TBA-active products were measured. Ratio of antioxidant enzymes activity to TBA-active products content (AOD/TBA) was calculated. It was determined, that in rat liver of I st experimental group, the activity of all antioxidant defense enzymes, glucose-6-phosphate dehydrogenase and content of TBA-active products increased. Under these conditions, the resistance of this tissue to oxygen free radicals, and AOD/TBA ratio also increases. In the II nd experimental group, the superoxide dismutase acti­vity was similar to control values, but other indices remained higher than in control group. Similar trend was observed in the thigh muscle of both experimental groups, where it was found that, activity of antioxidant enzymes and glucose-6-phosphate dehydrogenase increased, and the amount of lipid peroxidation products also elevated. At the same time, the AOD/TBA ratio was the highest in animals of the II nd experimental group. In testes of animals of the І ts experimental group, an increase in the glutathione peroxidase activity was established, and the content of TBA-active products was the highest among three groups. A rise in content of TBA-active products caused a decrease in AOD/TBA ratio in more than 4 times. In the II nd experimental group, it was found that the increase of antioxidant enzymatic activity and decrease of content of TBA-active pro­ducts, compared to the I st experimental group, caused an increase in AOD/TBA ratio. In brain tissue, glutathione peroxidase and catalase activity increased at a constant content of peroxidation products. This caused an increase in AOD/TBA ratio, that indicates growth of resistance to oxygen free radicals. Thus, the effect of long term per oral injection of taurine on the enzymatic link of antioxidant defense is tissue- and dose-dependent.