Roles Of UCHL1 Played In The Impaired Spermatogenesis In Artifical Cryptorchidism Mice

Testis is the place of spermatogenesis, and spermatogenic failure is an important cause of male infertility. Spermatogeneis in the testis are very sensitive to temperature, heat stress can lead to abnormal spermatogenesis, but its mechanism is not clear. According to our previous research, in spermatocytes showing early apoptotic morphological features, Uchl1 protein increased not only in abundance significantly, and its expression correlated with Jab1 and p27kip1 Protein, suggesting that Uchll protein in spermatocytes may be involved in the regulation to apoptosis of spermatogenic cells through a novel mechanism. Therefore, this project by establishing an artificial cryptorchidism mouse model, to obtain the relation between the spermatogenic disorder and the abnormal expression of proteins Uchll, Jab1 and p27kip1 in spermatogenesis, and the involved molecular mechanism.This study found that:(1) there is apoptotic spermatocytes (AC) and multinucleated giant cells (MC) in mouse cryptorchids, however, on the seventh day after operation AC has been detected, but MC just fourteenth days after operation was detected, indicating that the formation of MC was later than AC. So we suggested that apoptosis may be the initial reaction of testis spermatogenic cells to heat stress, and then the formation of MC is induced; (2) Jabl protein specifically bound to Uchll protein and testicular tissues, suggesting that Uchll protein may be involved in the regulation of apoptosis of spermatogenic cells through Uchl1/Jab1 pathway; (3) p27kipl was showed high expression in Sertoli cell in the testis of normal adult mice, but not in spermatogenic cells; in cryptorchidism model, in response to the heat stress, p27kip1 protein. Jabl and Uchll protein occurred synchronically in some spermatocytes, and mainly located in the nuclei of spermatocytes with apoptotic appearance. Thus we speculate, the specific higher environmental temperature of cryptorchids, the expression of Uchll protein was up-regulated in spermatocytes, causes the increase of p27kipl protein in the nucleus, and thereby promotes the apoptosis in spermatogenic cells.In conclusion, both the heat stress induced initial apoptosis of spermatocytes and subsequent formation of multinucleated giant cells are two main ways of spermatogenetic cell loss in cryptorchid testes, but only the former was related to Uchll. Uchll occurred abnormally in the spermatocytes in response to abdominal hypothermia, and in association with Jabl and p27kip1, can be used to specify the mechanisms of Uchll involvement in the heat-stress induced apoptosis of spermatocytes.In addition, this thesis also includes preliminary studies on uPA genetic deficient mice. Successful breeding of uPA-/-mice was done with checking the genotype uPA-/-, and its gene expression in uterine and ovarian tissue were detected; results on litter sizes suggested its fertility decline; at the same time, in order to seek the relevant molecular compensatory mechanism, the expression of MMP2 and MMP9 was detected.