Radioprotective effect of zinc aspartate on mouse spermatogenesis: a flow cytometric evaluation.

The radioprotective effect of zinc aspartate on spermatogonial cells of whole-body irradiated mice was studied using flow cytometry. Adult male Swiss albino mice were treated with 30 mg/kg body weight of zinc aspartate 30 min before exposure to 0, 0.5, 1, 2 and 3 Gy of gamma-radiation. The animals were killed 7 to 70 days postirradiation and the relative percentages of different germ cells were analyzed by flow cytometry. A significant increase (p<0.002, 0. 0001, 0.005 and 0.008 for 0.5, 1, 2 and 3 Gy, respectively) in the relative percentage of spermatogonial (2C) population was observed in mice treated with zinc aspartate before exposure to different doses of gamma-radiation, compared to the irradiated controls on day 35 posttreatment. Also mean of each radiation dose of all the intervals studied showed a significant (p<0.03) increase in the relative percentage of spermatogonia. Despite the increase in the relative percentage of spermatogonia, the relative percentage of tetraploid cells (4C) remained higher in the zinc aspartate treated mice, compared to the irradiated controls. However, there was no change in the haploid populations viz. round (1C) and elongated (HC) spermatids of the zinc aspartate pretreated animals compared to irradiated controls. These data suggests that zinc aspartate pretreatment protects spermatogonia and tetraploid cells from radiation-induced cell killing.