Effect of restraint stress on 2,3,7,8 tetrachloro dibenzo-p-dioxin induced testicular and epididymal toxicity in rats

Dioxins like 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) impair male reproductive system by increasing the generation of reactive oxygen species (ROS). Glucocorticoids have been found to suppress male reproductive function and also influence TCDD pathway. As stress is characterized by an increase in the level and activity of glucocorticoids, the present experiments were conducted to evaluate the effect of restraint stress on TCDD-induced testicular and epididymal toxicity. Adult male Wistar rats were subjected to either restraint stress (5 hours/day) or TCDD treatment (100 ng/kg b.w./day) or both for 15 days. Restraint stress or TCDD treatment raised the serum level of corticosterone and suppressed the testicular level of steroidogenic acute regulatory (StAR) protein and serum level of testosterone significantly. In the testis and epididymis, restraint stress or TCDD treatment raised the levels of lipid peroxidation and hydrogen peroxide and suppressed the activities of antioxidant enzymes significantly. In rats subjected to both restraint stress and TCDD treatment, a significant increase in the serum level of corticosterone and a significant decrease in the testicular level of StAR protein and serum level of testosterone were observed as compared to rats treated with TCDD alone. A significant increase in the levels of lipid peroxidation and hydrogen peroxide and a significant decrease in the activities of antioxidant enzymes were observed in the testis and epididymis of rats subjected to both restraint stress and TCDD treatment as compared to TCDD alone treated rats. Thus, restraint stress potentiates the adverse effects of TCDD on male reproductive organs.