Melatonin protects methotrexate-induced testicular injury in rats.

OBJECTIVE: Melatonin possesses anti-inflammation and anti-oxidant potentials. However, whether NF-E2 related factor 2 (Nrf2) pathway and nuclear factor-kappaB (NF-κB) pathway are involved in the protective effect of melatonin are unknown. We aim to explore the regulatory effect of melatonin on methotrexate-induced testicular injury. MATERIALS AND METHODS: Sprague Dawley (SD) rats were randomly assigned in sham group, methotrexate group and melatonin group, with 8 rats in each group. Testis tissues were collected 10 days after animal procedures. Pathological lesions and cell apoptosis in testis tissues were evaluated using HE (hematoxylin and eosin) staining and TUNEL assay, respectively. Oxidative stress in rat testis was accessed using relative commercial kits. Western blot was performed to detect protein expressions of relative genes in Nrf2 pathway and NF-κB pathway in rat testis tissues. RESULTS: Activities of SOD, GSH, CAT and T-AOC in testis homogenate in melatonin group were remarkably higher than those of methotrexate group (p < 0.05). On the contrary, levels of MDA, ROS and inflammatory factors (TNF-α, IL-1β, IL-6 and KC-GRO) were markedly decreased after melatonin treatment. Besides, melatonin group showed alleviated pathological lesions and cell apoptosis in testis. Western blot results demonstrated that melatonin treatment upregulated expressions of Nrf2, GSR, GCLm, HO-1 and NQO-1 in testis. However, protein expressions of NF-κB, TNF-α, VCAM-1, ICAM-1 and MCP-1 were downregulated. CONCLUSIONS: Melatonin protects methotrexate-induced testicular damage in rats by improving antioxidant capacity and inhibiting inflammatory response via Nrf2 and NF-κB pathways.