Melatonin alleviates Di-2-ethylhexyl phthalate induced male reproductive toxicity through inhibition of endoplasmic reticulum stress: Behavioral, biochemical, and morphological evidences

Abstract

Di(2-ethylhexyl) phthalate (DEHP) is one of the most commonly used plasticizers known for its effect on reproductive systems. The underlying molecular mechanism of DEHP-induced male reproductive toxicity is still less explored. Melatonin (Mel), a neurohormone possessing antioxidant properties, has demonstrated reproprotective effect in various studies. In this study, the underlying molecular mechanisms of DEHP induced reproductive toxicity and reproprotective effect of melatonin were investigated. Adult male Wistar rats were randomly divided into four experimental groups: control, DEHP-500 mg/kg, DEHP+Mel-3 mg/kg and DEHP+Mel-10 mg/kg. Animals were treated with DEHP (500 mg/kg; p.o.) for 28 days. Melatonin was administered at doses of 3 and 10 mg/kg for the last 14 days. DEHP exposure impaired the sexual motivational behavior as well as copulatory behavior in rats, which was ameliorated by melatonin treatment. In addition, Mel reversed the changes in the gonadosomatic index along with sperm quality and quantity. DEHP reduced the serum testosterone level and increased the level of testicular nitrite, and MDA while, decreased the level of reduced glutathione. However, Mel mitigated testicular oxidative stress and restored the serum testosterone level in DEHP-exposed rats. Additionally, histopathology and scanning electron microscopy revealed that the administration of Mel attenuates the cellular alteration as evidenced by Johnsen’s index scores. Western blotting analysis showed that protein expression of C/EBP homologous protein (CHOP), caspase-12, and glucose-regulated protein (GRP-78) were found upregulated in DEHP-exposed rat testes, indicating ER-stress mediated cell death. Mel reversed DEHP-induced protein expression level of CHOP, GRP-78 and caspase-12 in testicular tissue. In conclusion, the findings of the present study showed that Mel could be an effective intervention in the treatment of DEHP-induced reproductive toxicity. Moreover, ER-stress mediated apoptotic cells death played a vital role in DEHP-induced male reproductive toxicity.