Simultaneous increase in germ cell apoptosis and oxidative stress under acute unilateral testicular ischaemia in rats

Ischaemia induced germ cell apoptosis in rat testis was studied in detail to find out (i) spermatogenic stage or seminiferous epithelium region specific involvement of germ cells in apoptosis, (ii) preferential specificity of a particular germ cell type to become apoptotic and (iii) the ratio of live and dead testicular cells isolated in vitro after various period of ischaemic induction. Cell apoptosis, as observed in histological sections increased from 1 to 24 h of ischaemia. Apoptosis was not restricted to any specific germ cell type but was observed simultaneously in all the cell types in the initial hours (1-6 h) of ischaemia. No spermatogenic stage specific preference in apoptotic induction was also observed. However, as the duration of ischaemia progressed, the cell types observed to be most affected in number and morphology were the spermatids followed by spermatocytes. Centrally located tubules of testis were affected first than those located in the periphery. Overexpression of Bax staining was limited to few germ cell nuclei only. More than 95% of the germ cells in the control testis that earlier showed trypan blue dye exclusion were found stained after 12 h of ischaemia. Starting from early hours (1 h), lipid peroxidation rose proportionally with the duration of ischaemia while superoxide dismutase (SOD) and catalase activities were found decreased. Significant (p < 0.05) increase in the activities of glutathion-s-transferase and levels of hydrogen peroxide were observed after 6 h of ischaemia. These findings indicate that the physiological processes of oxidative stress have a direct linkage to the extent of germ cell apoptosis in the seminiferous epithelium.