[Dynamic changes of pH2AX expression in the reversibility of mouse testicular reproductive function impaired by single heat stress].

OBJECTIVE: To investigate the role of pH2AX in the reversibility of mouse testicular reproductive function impaired by single heat stress. METHODS: Twenty-four C57 male mice were randomly divided into heat stress and control groups and immersed in water at 43℃ and 25℃, respectively, for 15 minutes. At 1, 7, and 14 days of heat exposure, all the mice were sacrificed and their testis tissues collected for determining the apoptosis of the germ cells by TUNEL and measuring the expression level of the pH2AX protein by immunohistochemistry and Western blot. RESULTS: The highest percentage of apoptotic cells were found in the seminiferous tubules of the mice in the heat stress group on the 1st day of the exposure and almost no apoptosis was observed at 7 and 14 days. The pH2AX protein was expressed in the nuclei of the basement membrane of adjacent seminiferous tubules. Compared with the control group, the expression of pH2AX was significantly increased on the 1st day of exposure (0.47 ± 0.02 vs 1.61 ± 0.04, P <0.01), then decreased at 7 days (0.85 ± 0.03) in comparison with that on the 1st day (P <0.01), and again elevated at 14 days (1.72 ± 0.02) as compared with either those at 1 and 7 days (P <0.01) or that of the control (P <0.01). CONCLUSIONS: Heat stress causes dynamic changes of the pH2AX expression in the testis of the mouse, which are associated with heat stress-induced proliferation and division of the testicular spermatogenic cells.