Appearance of morphologically abnormal Sertoli cells in infertile PD male rats during postnatal development

Our previous studies using 12-week-old PD (pd/pd) male rats have indicated high incidence of morphologically abnormal Sertoli cells. Because sterility in these males is attributable to abnormal spermatogenesis, it is suggested that the abnormal Sertoli cells are related to abnormal spermatogenesis. In this study, the testes of prepubertal 7- and 21-day-old male pd/pd rats were examined ultrastructurally for the presence of abnormal Sertoli cells. The pd/+ males served as controls. At 7 days of age, light and dark types of Sertoli cells were found in pd/pd males. However, no anatomic abnormality existed in those cells. Cytoplasmic organelles were underdeveloped. The only difference between the light and dark Sertoli cells was the high electron density in the nucleus and cytoplasm of the dark cells. These features were similar between pd/pd and pd/+ males. At 21 days of age, the dark Sertoli cells had disappeared, and light Sertoli cells and abnormal Sertoli cells were observed in pd/pd males. The light Sertoli cells had well-developed cytoplasmic organelles. On the other hand, abnormal Sertoli cells had a dark appearance, irregularly shaped nuclei, and a large quantity of lipid droplets in the cytoplasm. These findings suggested the presence of functional disorders in lipid metabolism. The light and abnormal Sertoli cells also were found in pd/+ males; however, incidence of the abnormal Sertoli cells was significantly higher in pd/pd males (11.3%), compared with that in pd/+ males (4.9%). Thus, these results indicate that in pd/pd male rats, a number of abnormal Sertoli cells appear by 21 days of age.