Abstract
Histological testicular changes were investigated sequentially in WBN/Kob rats from 7 to 60 weeks of age. Severe atrophy of the seminiferous tubules was first observed in two out of five rats of 15 weeks of age. The severely atrophied tubules initially appeared in patches among the normal tubules and gradually spread throughout the testis. The testicular degeneration was progressive with advancing age, about 90% of all tubules in the testis being severely atrophied after 40 weeks of age. This degeneration was characterized by disappearance of germinal cells, a reduction in tubular diameters with thickening of the basement membrane, and slight Leydig cell hyperplasia. The number of BrdU positive germinal cells declined with advancing age. In electron microscopic examinations using a lanthanum tracer, the blood-testis barrier consisting of tight junctions between Sertoli cells was not disrupted in severely atrophied tubules. It was concluded that the testicular degeneration in WBN/Kob rats occurred from young age and there was no relationship between these lesions and diabetes.
