Morphometric Evaluation of Seminiferous Tubules in Aged Mice Testes after Melatonin Administration

OBJECTIVE Melatonin, the pineal gland hormone as a direct or indirect antioxidant and free radical scavenger, is involved in the process of both aging and age-related diseases. This study investigates the effects of melatonin on the histology of testicular seminiferous tubules in aged mice. MATERIALS AND METHODS Twenty male, white mice, aged 16 months, that weighed 20-23 gr were equally divided into control and experimental groups. The experimental group was intraperitoneally injected with a daily single dose of 10 mg/kg melatonin for 14 days. The control group received only saline. Six days after the last injection, all mice were sacrificed and the testes were excised and processed for light microscope observation. In the morphometric study, we evaluated testicular seminiferous tubule parameters such as height of germinal epithelium, seminiferous tubule diameter, thickness of interstitial connective tissue and spermatogenesis index (SI). SPSS software and student's t-test analyzed all parameters to assess the significance of changes between control and experimental groups. RESULTS Melatonin-treated mice had seminiferous tubules with a wide lumen lined by low height germinal epithelium. The interstitial connective tissue thickened significantly in the experimental group (p<0.05), tubular diameter and germinal epithelium height decreased significantly (p<0.01), and the SI reduced compared to the control group (p<0.001). CONCLUSION The results of this study showed the disadvantages of melatonin on seminiferous tubules of aged mice testes.