急性热应激对性成熟雄性小鼠睾丸、附睾、输精管中热休克蛋白70表达的影响

目的:探讨急性热应激对性成熟雄性小鼠睾丸、附睾、输精管中热休克蛋白70(heat shock protein 70,HSP70)表达的影响。方法:将32只8周龄雄性小白鼠随机均分为4组,饲养7d后,进行热应激处理,温度控制在(39±0.5)℃,时间分别为0.5、1和3h。应激后立即采血,分离血清测定谷草转氨酶(GOT)含量。一侧附睾制备精子悬液,用于计算精子密度和顶体畸形率;另一侧附睾、睾丸、输精管用于免疫组化研究。结果:应激后,小鼠体重、睾丸系数、顶体畸形率变化不显著(P>0.05),附睾系数和精子密度有不同程度的下降,GOT含量急剧升高(P<0.01)。随着应激时间的延长,小鼠精子密度呈递减趋势,顶体畸形率呈上升趋势。应激时间最短的0.5h组小鼠体重、睾丸系数、附睾系数的降幅反而最大。免疫组化法观察发现,HSP70在性成熟小鼠睾丸、附睾、输精管中均有表达。正常状态下,HSP70在睾丸组织间质细胞中少量表达,应激后分布于间质细胞核,此外在精母细胞核与精子细胞核中也有大量分布;附睾中HSP70主要分布于主细胞质,基细胞和亮细胞中没有表达,应激后附睾体的纤毛细胞中也发现大量棕色颗粒;输精管中HSP70主要定位在基细胞质,主细胞中不表达。随着应激时间的延长,HSP70在睾丸、附睾中的表达量明显升高,而在输精管中的增幅不明显。结论:急性热应激对性成熟雄性小鼠的生殖系统造成了损伤;HSP70在睾丸、附睾、输精管中的表达与定位具有区域特异性和细胞特异性,提示其可能参与精子的发生与成熟;HSP70在应激状态下表达量大幅上升的作用可能在于保护细胞免受高热损伤。

Acute Heat Stress Increases HSP70 Expression in the Testis, Epididymis and Vas Deferens of Adult Male Mice

Objective ： To investigate the effects of acute heat stress on the expression patterns of heat shock protein 70 （ HSP70 ） in the testis, epididymis and vas deferens of adult male mice. Methods ： Thirty-two 8-week-old male mice were randomly divided into a control and 3 heat stress groups. After a week of pretreatment, the latter 3 groups were exposed to heat stress at （ 39 ± 0.5 ） ℃ for 0.5, 1 and 3 hours, respectively, followed immediately by collection of the blood and determination of glutamic oxaloacetic transaminase （GOT） concentration. Sperm suspension was made from one epididymis for the detection of sperm concentration and abnormal acrosome rate, while the testis, epididymis and vas deferens on the other side were harvested for immunohistochemical analysis. Results ： Heat stress induced different degrees of decrease in epididymis indexes and sperm concentration and a dramatic increase in GOT concentration （P 〈 0.01 ）, but caused no significant changes in the body weight, testis indexes and abnormal acrosome rate in the mice （ P 〉 0.05 ）. There was a tendency of gradual descent in sperm concentration and ascent in abnormal acrosome rate with the increasing time of heat stress. The most decrease in body weight, testis indexes and epididymis indexes was observed in the 0.5 h group. Immunohistochemical results showed that HSP70 was expressed in the testis, epididymis and vas deferens, mildly in the Leydig cells of the testis and distributed in the nuclei of the Leydig cells, spermatoblasts and spermatocytes. In the epididymis, HSP70 was expressed mainly in the cytoplasm of principal and ciliated cells, but not in the basal and clear ceils, while in the vas deferens, it was observed mainly in the cytoplasm of the basal cells, but not in the principal cells. With the increase of heating time, the HSP70 expression was markedly elevated in the testis and epididymis, but not so obviously in the vas deferens. Conclusion： Acute heat stress was harmful to the reproductive system of