Seasonal changes in spermatogenic cell degeneration in the seminiferous epithelium of adult Japanese macaques (Macaca fuscata fuscata)

Abstract

ABSTRACT. The degenerating pattern of spermatogenic cells in the seminiferous tubule of Japanese macaques was studied to clarify a relationship between seasonal changes of reproductive performances and cytological findings in the Japanese macaque. For light microscopy, testis samples were obtained from five adult animals by biopsy in April (nonmating season) and October (mating season). For electron microscopy, specimens from four additional macaques were used. Degenerating cells were found in all steps of spermatogenesis. In stages I to V of the cycle of the seminiferous epithelium, morphologically atypical pachytene spermatocytes were observed in 14.7 and 10.0070 of the cells in the nonmating and mating seasons, respectively, although the difference in percentage was not significant. Mature spermatids with atypical features in those stages occupied 59.6~ of the cells in the nonmating season, which significantly decreased to 34.1% in the mating season. These results imply that the seasonal change of sperm production is related, at least in part, to the process of degeneration of the spermatogenic cells in this species.

Testicular histological examination of spermatogenetic activity in captive gorillas (Gorilla gorilla)

“…This indicates that meiosis had progressed, but the subsequent step of spermiogenesis did not occur. It has been reported that some spermatogonia, spermatocytes, and spermatids degenerate through spontaneous apoptosis in Macaca fuscata [Enomoto et al, 1995] and humans [Hikim et al, 1998]. Detailed studies remain to be performed in the gorilla; however, in the current study, all spermatocytes in samples 5 and 6 underwent degeneration.…”

Molecular histology of spermatogenesis in the Japanese macaque monkey (Macaca fuscata)

“…Pioneering histological studies examined spermatogenesis in this species via morphological observation with HE or PAS staining. These efforts provided basic insights into seminiferous cycles (Nagato et al 1994) and seasonal reproductive changes (Enomoto et al 1994(Enomoto et al , 1995. However, classical histological methods relied largely on the researchers' proficiency-an approach which created difficulty in accurate validation, reproducibility, and technical convenience.…”

“…Spermatogenesis enters the preparatory stage in juveniles, and full spermatogenesis is achieved in adulthood. Regarding the Japanese macaque, pioneering studies have characterized the morphology of spermatogenic cells by classical histological strategies, such as hematoxylin-eosin (HE) or periodic acid-Schiff (PAS) staining (Enomoto et al 1994(Enomoto et al , 1995Nagato et al 1994). These observations also implied the presence of seasonal changes in spermatogenesis, which include less spermatogenic activity (Enomoto et al 1994) and degeneration of spermatogenic cells (Enomoto et al 1995) in the nonmating season.…”

“…Regarding the Japanese macaque, pioneering studies have characterized the morphology of spermatogenic cells by classical histological strategies, such as hematoxylin-eosin (HE) or periodic acid-Schiff (PAS) staining (Enomoto et al 1994(Enomoto et al , 1995Nagato et al 1994). These observations also implied the presence of seasonal changes in spermatogenesis, which include less spermatogenic activity (Enomoto et al 1994) and degeneration of spermatogenic cells (Enomoto et al 1995) in the nonmating season. However, only a few subsequent studies have targeted precise molecular characterization of spermatogenesis based on cell type-specific antigens (Tokunaga et al 1999;Yu and Takenaka 2004).…”