Spermatogonial stem cell transplantation and subsequent orchidopexy in the bilateral cryptorchid mouse model

Testicular cell transplantation has been widely used to investigate the restoration of fertility in rodent models. In this research we apply transplantation as a treatment method in the cryptorchid model and compare this method with orchidopexy, which is the routine treatment for this problem. We studied the controversial effects of treatment on the number of germ cells and other morphometrical characteristics of testicular and epididymal parameters in cryptorchid mice.

Bilateral cryptorchidism was induced in immature mice by returning two testes to the abdominal cavity via a surgical procedure. Respectively orchidopexy and transplantation of spermatogonial stem cells (were isolated from bilateral cryptorchid testes) with later orchidopexy was performed two and three months after heat exposure in separate cryptorchid mice. The weight of testes, spermatogenic cell numbers, as well as epididymal sperm parameters were measured at two and eight weeks after treatment. The results were analyzed by performing ANOVA and Tukey's tests.

Our results showed that after orchidopexy, the testis remained atrophied and the number of spermatogonia returned to the near normal range, but spermatogenesis was recovered only partially at the stage of differentiated germ cells. After transplantation we observed significant changes in the stage of sperm formation compared to orchidopexy.

We demonstrated that the spermatogonia isolated from bilateral cryptorchid mice have the ability to regenerate spermatogenesis. Also, while orchidopexy is a routine treatment for cryptorchidism, transplantation may thus prove to be a promising technique for the preservation of fertility for severely damaged cryptorchid testes that have scarce spermatogonia.