The Expression Study Of The Local Regulation Factor In Yak Testis Associated With Age And Season

Bos Grunniens is Tibetan Plateau specialty livestock, which lived at an altitude of 3,000 meters above and adapted strongly to alpine cold and hypoxic environment. Study the morphological structure and regulation of related factors in the testicular of yak which in the different stages of the same breeding season and the same developmental stage of different breeding seasons. It is great significant to analyze hormonal regulation and spermatogenetic function of testicular in yak on the alpine cold and hypoxic environment adaptability studies. This study used histochemistry staining and immunohistochemical technique to analyze the distribution characteristics of related factors which included testis hormonal regulatory factors(VEGF、VEGFR2、TGFβ-1、TGFβR-Ⅰ)and blood-testis barrier regulatory factors(MMP-2、TIMP-2、VE-Cadherin)in yak in different developmental stage and different breeding season. It used to explore and compare the changes of each factor of cryptorchidism and normal testis in yak.Yak testicles internal structure has obvious change before and after sexual maturity and it are stabilized after sexual maturity. Testicles internal morphological structure showed seasonal variation when it enter the sexual maturity. It has closely relation with its exuberant spermatogenesis.1. The expression of testis hormonal regulatory factors and blood-testis barrier regulatory factors in different developmental stages of the yak testicles increased with age and stabilized after sexual maturity. It suggested that the change with age of testicular hormone regulation was associated with vascular development.2. The statistic dates showed that the average optical density of TGFβ-1 and its receptors in breeding season was lower than non-breeding season in adult yak testis. Besides, the average optical density of VEGF and its receptors, MMP-2 and TIMP-2 and VE-Cadherin in breeding season was higher than non-breeding season in adult yak testis. Testicular local regulation related factors were mainly expressed in the Sertoli cells, vascular endothelial and Leydig cells. Therefore, yak hormone secretion and spermatogenesis may be adjust the local vascular regulation related factors to change vascular permeability to involved in regulation of testicular function in different breeding season.3. In plateau environment, the cryptorchidism vascular of Yak was suffocated, the seminiferous function was seriously affected by the different degree of fibrosis and calcification in parenchyma; but the growth degree of unilateral normal testis was decreased compared with the normal tissue. Our results suggest that the VEGF and its receptors may serve as regulators to participate in the bilateral testicular spermatogenic suppression effect.Consequently, testosterone secretion and spermatogenesis of yak in plateau environment adjust the vascular development and change vascular permeability to involved in regulation of testicular function. VEGF and VEGFR2 may serve as regulators to participate in the bilateral testicular spermatogenic suppression effect. It will be of great importance in maintaining a certain reproductive function.