The effect of cryptorchidism on the quantitative histology, histochemistry and hydrolytic enzyme activity of the rat testis.

Cryptorchidism of the mature rat testis led to degeneration of the seminiferous tubules and changes in enzyme patterns and activities. Spermatogenic stages 1-4, containing pachytene primary spermatocytes in late meiotic prophase, and stage 5, containing recently formed round spermatids, were damaged by 48 h. Within 96 h stages showed a loss of germinal cells into the lumen and this was almost complete by 192 h. Acid phosphatase showed increased histochemical activity in the basal area of the seminiferous tubule up to 96 h of cryptorchidism, and at 192 h much of the activity was located in large lipidcontaining bodies within the remaining seminiferous epithelium. Total and free biochemical acid phosphatase decreased during cryptorchidism in parallel with cell loss; there were no significant changes in total cathepsin D activity but free enzyme activity was increased throughout the experimental period indicating increased lability of lysosomes in the Sertoli cell. Lactate dehydrogenase activity was mainly tubular but succinate dehydrogenase also showed interstitial activity. Lipoamide dehydrogenase (NADH) was found mainly in the interstitium. During cryptorchidism both lactate and succinate dehydrogenase activity decreased in the tubules parallel to the loss of germinal cells, whereas lipoamide dehydrogenase (NADH) activity increased in both interstitial and tubular areas. It is suggested that the initial lesion in the seminiferous epithelium, produced by cryptorchidism is in the Sertoli cell and that germ cell damage may result from reduced function of the Sertoli cell.