Stimulation of Spermatogenesis and Synthesis of Testosterone by Allotransplantation of Neonatal Testicular Tissue under Tunica Albuginea of Cryptorchid Testis

The abdominal type of cryptorchism was modeled on random-bred albino rats by replacing both testes from the scrotum into the abdominal cavity for 3 weeks; thereupon they were manipulated into the scrotum. In control rats, no additional surgery was performed. In experimental rats, the testicular tissue obtained from 1-2-day rat pups was transplanted under testicular tunica albuginea. Prior to orchiopexy, the weight of testes decreased by 62.5-64.1%. In 6 month after the surgery, it increased by 36.1% in the control group, whereas in experimental rats the weight of testes elevated by 123.2% and approximated the normal value. Histologically, the control group demonstrated persistent disturbance in spermatogenesis with emptiness of numerous seminiferous tubules where only Sertoli cells could be revealed and with pronounced dystrophic alterations in the spermatogenous epithelium of the partially preserved tubules where spermatogenesis was blocked at the spermatogonial level. In contrast, the transplantation region of the experimental testes exhibited formation of novel mature testicular tissue enclosed by a connective tissue capsule incorporating the seminiferous tubules with differentiated epithelium and with the clusters of Leydig cells in the stroma. In 6 month, spermatogenesis was observed in most seminiferous tubules of the host testicular tissue, which had spermatozoa in the lumens. To the moment of orchiopexy, the blood testosterone decreased by about 2.5-fold. In control group it remained diminished during entire observation period (up to 6 month), while in the experiment group its level normalized completely as early as in 2 month and remained even elevated to the end of observation period.