The natural course of cryptorchidism in rats and the efficacy of orchidopexy or orchidectomy in its treatment before and after puberty.

Both clinical and experimental evidence suggest that fertility is impaired in unilateral cryptorchidism. To investigate the effect of the undescended testis on the contralateral descended gonad, a new experimental model based on natural cryptorchidism in rats was designed. Seventy male Buffalo rats with an undescended right testis noted at the age of 30 days were used. Fifty healthy animals served as a controls. The natural course of cryptorchidism was investigated at the ages of 30, 90, and 180 days. The effects of orchiopexy and orchiectomy performed in cryptorchid animals before and after puberty were evaluated at the age of 180 days. Both nonoperated and operated animals were mated at the age of 150 days in order to estimate their fertility. The animals were killed at 30, 90, and 180 days of life and the testes were removed. In each excised testis testicular weight and seminiferous tubular diameters were measured and the maturity of the germinal epithelium was determined using the Johnsen testicular biopsy score. The experiment demonstrated reduced testicular weight and seminiferous tubular diameters in undescended testis already at 30 days and arrest of spermatogenesis at the spermatocytes stage at 90 and 180 days. There was no significant difference between contralateral descended testes and controls at the age of 30 and 90 days, but at 180 days the degenerative changes were identical with those in the cryptorchid testes. Cryptorchid rats were completely infertile. Both orchiopexy and orchiectomy prevented the damage to the contralateral testis. A significant improvement in size and spermatogenesis was recorded in most cases of the surgically descended testes.(ABSTRACT TRUNCATED AT 250 WORDS)