Spatially heterogeneous restoration of spermatogenesis in the mouse testis following experimental cryptorchidism and orchidopexy

Spermatogenesis is a highly temperature-sensitive process that occurs within the testis and is rapidly impaired upon exposure to abdominal heat. Although spermatogenesis may recover once heat stress is relieved, it remains unclear whether this restoration occurs uniformly within the three-dimensional architecture of the testis. In the present study, we combined experimental cryptorchidism and orchidopexy in adult mice with deep learning-based whole-organ three-dimensional reconstruction. Following 8 weeks of cryptorchidism, markedly impaired segments accounted for 94% of the total tubule length. Ten weeks after orchidopexy, although 87% of the tubule length returned to a normal state, the remaining impaired segments were preferentially located near the rete testis and immediately beneath the tunica albuginea. In the cryptorchid testis, type A spermatogonia were not reduced beneath the tunica albuginea. Incomplete restoration beneath the tunica albuginea was not detected in the vitamin A-deficient testis after the switch to a vitamin A-containing diet. These results suggest that the incomplete restoration beneath the tunica albuginea arises after orchidopexy and may be specific to cryptorchidism. This knowledge may help optimize sperm retrieval, although verification in the human testis is required.