Retinoic acid: A potential therapeutic agent for cryptorchidism infertility based on investigation of flutamide-induced cryptorchid rats in vivo and in vitro

•The concentration of retinoic acid was lower in cryptorchid testis compared with normal testis.•The sperm quality of cryptorchid testes treated with retinoic acid injection was better than that of the untreated cryptorchid model.•Retinoic acid was associated with blood-testis-barrier protein levels that were improved relative to the untreated control, in vivo and in vitro.•A testis organotypic culture system was used to study the effect of retinoic acid on cryptorchidism in vitro. Cryptorchidism is a common disorder in children and may cause infertility in adults. The BTB is essential for maintaining the microenvironment necessary for normal spermatogenesis. This study investigated whether retinoic acid (RA) may regulate the proteins that are essential for integrity of the BTB in cryptorchidism. Female Sprague-Dawley rats were administrated flutamide during late pregnancy to induce a model of cryptorchidism in male offspring. The concentrations of RA and BTB tight and gap junction protein levels were significantly lower in untreated cryptorchid pups compared with normal pups, but almost normal in cryptorchid pups given RA. Studies in vitro corroborated these findings. The sperm quality of RA-treated model pups was better compared with the untreated model. RA treatment may have therapeutic potential to restore retinoic acid and proteins associated with integrity of the BTB in cryptorchid testis.