Toyama Y, Ohkawa M, Oku R, Maekawa M, Yuasa S
Department of Anatomy and Developmental Biology, School of Medicine, Chiba University, Japan.
J Androl. 2001 May-Jun;22(3):413-23.
Newborn rats were treated with 10 microg of diethylstilbestrol (DES) on alternate days from the 2nd to the 12th postnatal day, and the testes were sequentially examined up to 105 days of age by light, electron, and confocal laser microscopy. In control rats, spermatozoa and step 19 spermatids were observed in stage VIII seminiferous tubules at 56 days of age. Spermatogenic cells in DES-treated rats differentiated normally from birth until 21 days of age, after which differentiation continued only to the pachytene-spermatocyte stage. From this age onward, spermatogenic cells older than pachytene spermatocytes were not found until 56 days of age. After this point, the cells resumed differentiation and finally became spermatozoa by 91 days of age; that is, 35 days later than control rats. Electron and confocal laser microscopy showed that in the normal rat, the formation of the ectoplasmic specialization between adjoining Sertoli cells was observed as early as 20 days of age. In contrast, the specialization was not formed until 56 days of age in DES-treated rats. Furthermore, the delay in functional maturation of this structure as the blood-testis barrier was confirmed by intercellular tracer experiments. It is clear that neonatal administration of DES delayed the establishment of the blood-testis barrier for 4 weeks. Consequently, during this period, pachytene spermatocytes were exfoliated from the seminiferous epithelium without completion of meiosis.
新生大鼠在出生后第2天至第12天隔天接受10微克己烯雌酚（DES）处理，并通过光学显微镜、电子显微镜和共聚焦激光显微镜对睾丸进行连续检查，直至105日龄。在对照大鼠中，56日龄时在VIII期生精小管中观察到精子和第19步精子细胞。DES处理的大鼠生精细胞从出生到21日龄正常分化，此后分化仅持续到粗线期精母细胞阶段。从这个年龄开始，直到56日龄才发现比粗线期精母细胞更成熟的生精细胞。此后，细胞恢复分化，最终在91日龄时变成精子，即比对照大鼠晚35天。电子显微镜和共聚焦激光显微镜显示，在正常大鼠中，早在20日龄时就观察到相邻支持细胞之间形成了外质特化。相比之下，DES处理的大鼠直到56日龄才形成这种特化。此外，通过细胞间示踪实验证实了作为血睾屏障的这种结构功能成熟的延迟。显然，新生期给予DES使血睾屏障的建立延迟了4周。因此，在此期间，粗线期精母细胞从生精上皮脱落，减数分裂未完成。
