Apoptosis and cell removal in the cryptorchid rat testis.

In order to determine that apoptosis is responsible for large-scale germ cell elimination, we analyzed cells from cryptorchid testes both in histological sections and among those isolated in vitro. Apoptotic testicular cells during 3 to 7 days were only 8 to 30%, reaching a maximum of 80% by the end of 15 days of cryptorchidism. A similar trend was also observed with the number of dead cells. The process of large-scale germ cell removal in the initial stages was facilitated by the formation of multinucleated giant cells, which stained negative for apoptosis. Increase in oxidative stress and decrease in intratesticular testosterone was also observed. The above findings indicate that large-scale germ cell removal, at least during initial stages of cryptorchidism is not solely as a result of apoptosis. Declined intra testicular testosterone, elevated temperature and high oxidative stress following cryptorchidism probably affect cell viability and trigger a fast pace cell removal through giant cell formation.