Zinc modulates heat-induced degenerative effects in mice testes

This study was designed to investigate whether administration of zinc sulphate could improve the response of mouse testis to degenerative effects of short term exposure heating. Fifty-four adult male Balb/C mice were anaesthetized and the scrotums of 36 of them were immersed for 15 min in a waterbath at 43°C. Immediately after the heating, half of the heated animals (n = 18) were injected with saline solution (HS) and the other half (n = 18) were given 10 mg/kg of zinc sulphate intraperitoneally (HZ), and this was continued every other day for 60 days. Control group of mice (n = 18) were treated identical to the HS group with the exception that the waterbath was held at 23°C. Mice were sacrificed at 15, 30 and 60 days after heating and the testes were gently excised. Seminiferous tubules diameter and percentage of spermatogenesis were measured in each testis. There was a significant reduction in the mean seminiferous tubules diameter and the percentage of spermatogenesis up to day 30 after heating in the HS group in comparison with the control group (172.5 ± 2.55 µm vs 208.2 ± 1.53 µm and 18.00 ± 0.77% vs 99.33 ± 0.33%, respectively) but in the HZ group, only initial decline (up to day 15) was observed in the mean seminiferous tubules diameter (199.1 ± 1.90 µm vs 206.0 ± 2.51 µm, not significant) and the percentage of spermatogenesis (91.33 ± 0.95% vs 97.67 ± 0.66%, P<0.001); then, a progressive recovery was seen up to the end of the experiment. Histopathological observations showed progressive degeneration up to day 30 after heating and then normal structure was returned in the HS group. In the HZ group, normal structure was returned up to day 15. The results from this study indicated that administration of zinc sulphate may improve the spermatogenesis process after testicular damage caused by a short term exposure of the mouse testis to heat.