Background: The objective of this study is to examine the histological effects of zinc and melatonin, alone or in combination, on rat testes.
Methods: For this purpose four study groups of ten Sprague-Dawley male rats were formed and treated for one month as follows: (1) Controls; (2) Rats injected with 3 mg/kg/day zinc, as zinc sulfate; (3) Rats injected with 3 mg/kg/day melatonin and (4) Rats injected with 3 mg/kg/day each zinc and melatonin.
Results: After four weeks the rats treated with melatonin showed inhibited spermatogenesis, testicular tubular degeneration and necrosis, obstruction of tubular lumen and lymphocytic infiltration. The two zinc-treated groups showed no histological differences to controls but the melatonin-only group showed inhibited spermatogenetic activity, tubular degeneration and necrosis, as well as obstruction of tubule lumens and lymphocytic infiltration.
Conclusion: The obtained results suggest that 4-week treatment with melatonin leads to histological and physiological impairments of testis and that zinc supplementation might offset these damaging effects (Tab. 2, Fig. 4, Ref. 12).