Reduced germ cell apoptosis during spermatogenesis in the teratospermic domestic cat

Teratospermia (>60% morphologically abnormal sperm/ejaculate) is associated with increased sperm output in the domestic cat. The objective of this study was to determine whether increased sperm production in teratospermic donors was associated with disturbances in germ cell apoptosis, the usual mechanism for sperm cell elimination. Apoptosis was measured by evaluating DNA fragmentation, expression of Caspase-3, and anti-apoptosis repressor with caspase recruitment domain (ARC) in the testes of normospermic compared with teratospermic cats. Testes (n = 6 males/group) were obtained by bilateral castration and immediately fixed in Bouin solution. Results revealed that greater than 97% of cells labeled as DNA fragmented were tubular regardless of male type. Fewer (P < .05) apoptotic spermatogenic cells per tubule (0.52 +/- 0.11 cells/tubule, x +/- SEM) and per 100 Sertoli cells (3.79 cells/100 Sertoli cells) were observed in teratospermic compared with normospermic (1.25 +/- 0.36 cells/tubule and 6.44 cells/100 Sertoli cells) cats. Among the spermatogenic cells, fewer (P < .03) spermatocytes were positively labeled in teratospermic (0.3 +/- 0.07/tubule) compared with normospermic (0.83 +/- 0.28/tubule) counterparts. Neither donor type differed in Caspase-3 or ARC expression activity. However, each factor was both cell- and stage-specific in expression. Specifically, Caspase-3 was located in Sertoli cells, A-spermatogonia, and round spermatids at stage V. The ARC was found in primary spermatocytes at each stage of the spermatogenic cycle. These results demonstrate that the high incidence of morphologically abnormal sperm in teratospermic male cats is accompanied by a reduced elimination of defective spermatogenic cells via apoptosis.