关键词: 山羊, 热应激法, 血睾屏障, 超微结构

Abstract:

The aim of this study was to investigate the effects of heat stress on the structure and function of blood-testis barrier (BTB) in goats, and to provide a theoretical basis for the prevention and treatment of heat stress in goats. Six healthy male Guanzhong goats aged 1 to 1.5 years old were selected and randomly divided into two groups with three goats in each group. Goats in the control group were fed normally, and the heat stress model was established in the experimental group by the modified scrotal heat stimulation method. The semen quality was detected by CASA, the testicular structure was observed by light microscopy and transmission electron microscopy, the permeability of BTB was detected by biotin tracer, and the expression and localization of key proteins of BTB were detected by Western blot and immunohistochemistry. In heat stress group, the testis index, spermatozoa count, spermatozoa viability, spermatozoa total motility and progressive motility were significantly decreased (P < 0.05). Heat stress caused obvious morphological damage of the testis, and the number of spermatogenic cells decreased and the arrangement was disordered. Endoplasmic reticulum of sertoli cells was expanded and a large number of vacuoles appeared. The tight junction between sertoli cells was loose and discontinuous. The permeability of BTB increased, and the expression level of key junction proteins decreased significantly (P < 0.05), but the distribution and location of BTB were not affected in heat stress group. Heat stress damages the morphology of goat testis, destroys the structure of sertoli cells and reduces the expression of key BTB proteins, thereby impairing the structural and functional integrity of BTB, resulting in the decline of spermatozoa quality and affect the reproductive capacity of male goats.

Key words: goat, heat stress method, blood-testis barrier, ultrastructure