Melatonin pretreatment attenuates 2-bromopropane-induced testicular toxicity in rats.

2-Bromopropane (2-BP) was used as an alternative for ozone-depleting solvents, which caused reproductive disorders in male workers and laboratory animals. A recent study indicated that 2-BP impaired antioxidant cellular defences and enhanced lipid peroxidation (LPO). Melatonin is a powerful endogenous antioxidant. We hypothesized that reactive oxygen species (ROS) and lipid peroxidation are involved in 2-BP-induced testicular toxicities. To test the hypothesis, we investigated the effects of melatonin on 2-BP-induced testicular toxicities. Rats were intraperitoneally injected with 2-BP (1g/kg) with or without melatonin (5mg/kg), then sacrificed on 7th day after 2-BP injection. Epididymal and testicular tissues were examined for biochemical and histopathological changes. Apoptotic cells in testis were detected by TUNEL staining and immunohistochemistry for active caspase-3. Exposure to 2-BP significantly decreased epididymal sperm count and morphological normal sperms. 2-BP also induced vacuolation and atrophy of the seminiferous tubules, reduction of spermatogonia and apoptosis of germ cells. 2-BP significantly increased TBARS levels in plasma and epididymis, and decreased GSH content in testis and epididymis. Pretreatment with melatonin counteracted 2-BP-induced oxidative stress, ameliorated apoptosis in testis and attenuated histopathological damage in testis. In addition, pretreatment with melatonin significantly attenuated 2-BP-induced sperm morphological changes. We conclude that pretreatment with melatonin attenuates 2-BP-induced testicular toxicity through its ROS scavenging and anti-apoptotic effects.