Deoxyribonucleic acid replication and germ cell apoptosis during spermatogenesis in the rabbit.

A deeper understanding of the occurrence of some events, such as DNA replication or germ cell apoptosis during spermatogenesis, is important for improving our understanding of seminiferous epithelium biology. However, studies on these events have been restricted to small rodents. This paper analyzes the occurrence of DNA synthesis by bromo-deoxy-uridine labeling, as well as the incidence of germ cell apoptosis by the TUNEL assay in the rabbit. In contrast to previous descriptions of spermatogonium proliferation in this animal, our results indicate that DNA replicates at stages 8/1, 2, 4, 5, 6, and 7, which are equivalent to the stages at which DNA synthesis occurs in rats and mice. Apoptosis of both spermatogonia and spermatocytes generally occurred at stages 2 and 4, when late spermatocytes end the pachytene stage or undergo meiotic divisions, and these results are consistent with previous observations in the rat testis.