Effect of vitamin e on ecg, blood lipid peroxidation and antioxidant enzyme activity in experimentally-induced hypothermic guinea-pigs

This study was carried out to determine the effects of vitamin E treatment on electrocardiogram (ECG), blood lipid peroxidation and antioxidant enzyme activity in experimentally-induced hypothermic guinea-pigs. Thirty healthy male guinea-pigs, weighing 500-800 g were used. After one week of adaptation period, guinea-pigs were randomly divided into three experimental groups: control (C), hypothermic (H) and vitamin E-treated hypothermic (Vit E+H), each containing 10 animals. Guinea-pigs in Vit E+H group were given orally 460 mg/kg vitamin E for four days before hypothermia induction. Twenty four hours after the last vitamin E treatment, guinea-pigs in H and Vit E+H groups were cooled by immersion into cold water (10-12 0C), and the control rats were immersed into water of body temperature (37 0C) up to the neck without using any anesthetic or tranquilizer for 5 minutes. Immediately after the cooling, rectal body temperatures were measured and ECG recordings were made. After the ECG recording, blood samples for the measurements of malondialdehyde (MDA) and glutathione (GSH) levels, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzyme activities were collected into heparinized and non-heparinized test tubes by cardiac puncture under an ether anesthesia. In hypothermic group, body temperature decreased significantly. Complete heart block and J wave were observed as ECG findings. In addition, MDA level was higher, SOD level was un-changed, and GSH level and GSH-Px enzyme activity were lower in hypothermic group. Although body temperature was significantly lower in vitamin E treated hypothermic guinea-pigs, findings observed in hypothermic group were not observed in this group. Thus, it was concluded that vitamin E treatment might prevent the hypothermia-induced lipid peroxidation and alterations in ECG, and increase the activity of antioxidant defense system.