The effect of the excision of future scrotal skin on testicular descent in neonatal rats: a new experimental model of cryptorchidism.

The ingunoscrotal skin of neonatal rats was widely excised on either the right or left side to examine the role of the scrotum in testicular descent. At the age of 10 days, gubernacular migration was observed to be significantly inhibited on the operated side in comparison with that on the nonoperated side. At the age of 60 to 90 days, 12 of 17 testes on the operated side were located in the superficial inguinal position, 2 were in the perineum, and another 3 had descended into the contralateral nonoperated scrotum. All the testes descended into the scrotum on the nonoperated side and in the normal control rats. Though the histological development was remarkably inhibited in the cryptorchid testis, the contralateral descended testis did show the same histological appearance as that of the control testes in 90-day-old rats. This new model of cryptorchidism is considered to provide a simple technique for investigating the mechanism of testicular descent and the impaired development of the testes in cryptorchidism.