Melatonin Ameliorates Heat Stress Induced Dysregulation of Testicular Function In Wistar Rat By Restoring Tissue Health, Hormone And Antioxidant Status And Modulating Heat Shock Protein Expression

Life Sciences-Physiology for Improved Therapy

Abstract

Hyperthermia results in changes in spermatozoa and ultimately causes infertility by inducing heat-stress related oxidative stress. Melatonin is a potent endogenous antioxidant and free radical scavenger. However, the efficacy of melatonin to protect the testis from the deleterious effects of hyperthermia is not clear entirely. This study was intended to look into the protective effect of melatonin against the testicular damage inflicted by thermal stress in adult rats. We investigated the consequences of hyperthermiainduced changes in hormones, antioxidant system, and the status of heat stress proteins in testes of rats and the effectiveness of melatonin to prevent these changes. Heat stress was induced at 43°C for 30 min/day for 15 consecutive days, using a hyperthermia induction chamber. Four groups of rats (n=6 per group) consisting of a control group, heat-stressed group, melatonin group and melatonin treated heat stress group of rats were considered for the study. Analysis of blood and testicular tissue of heat-stressed rats exhibited a significant reduction in serum testosterone, testicular superoxide dismutase, catalase, glutathione and 17β-HSD3; whereas, a significant rise in serum corticosteroid and testicular lipid peroxidation, along with the substantial increase in testicular HSP72 and HSP90 and HSF-1 expressions were also observed. In testicular histology of rats, exposed to heat stress alone, revealed remarkable germ cell degeneration and tubular deformations. Melatonin treatment in heat-stressed rats significantly prevented the afore mentioned heat stress-related alterations of physiological parameters. The results indicates that consumption of melatonin may substantially protect testis from heat-stress -induced testicular dysfunctions.