Effects of vitamin E on reactive oxygen species-mediated 2,3,7,8-tetrachlorodi-benzo-p-dioxin toxicity in rat testis

This study was undertaken to investigate whether treatment with vitamin E protects rat testis from oxidative stress induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Male rats of Wistar strain were administered TCDD at doses of 1, 10 and 100 ng kg(-1) body wt. day(-1) for 45 days. Other groups of animals were co-administered TCDD (1, 10 and 100 ng kg(-1) body wt. day(-1)) and vitamin E (20 mg kg(-1) body wt. day(-1)) for 45 days. Animals administered TCDD and those co-administered TCDD and vitamin E did not show any significant change in body weight. Administration of TCDD decreased the weights of the testis, epididymis, seminal vesicles and ventral prostate. The daily sperm production decreased in the animals administered TCDD from the control values of 22.19 +/- 2.67 to 13.10 +/- 3.16 x 10(6). There was a significant decline in the activities of superoxide dismutase, catalase, glutathione reductase and glutathione peroxidase with concomitant increased levels of hydrogen peroxide and lipid peroxidation. Co-administration of TCDD and vitamin E did not show any significant changes in the weights of the testis, epididymis, seminal vesicles and ventral prostate. The daily sperm production remained unchanged in the animals co-administered TCDD and vitamin E. The activities of antioxidant enzymes and the levels of hydrogen peroxide and lipid peroxidation did not change in the animals co-administered TCDD and vitamin E. The results suggested that administration of TCDD induces oxidative stress in testis, and vitamin E could impart a protective effect against TCDD-induced oxidative stress.