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目的探讨内质网应激IRE1信号通路在急性热应激诱导睾丸生殖细胞凋亡中的作用。方法 24只成年ICR雄性小鼠,随机分为4组。将热处理组小鼠身体的下1/3部分(包括阴囊、后腿和尾巴)浸于43℃恒温水浴中15 min,于热处理后0.5、2和6 h取睾丸组织。将对照组小鼠下腹部浸入22℃水浴15 min,6 h后取睾丸组。采用TUNEL法检测睾丸组织生殖细胞凋亡;用半定量RT-PCR技术检测u XBP-1/s XBP-1 mRNA表达;用Western blot检测睾丸总蛋白p-JNK表达。结果单次热应激能够明显诱导小鼠睾丸生殖细胞凋亡。与对照组相比,热处理能够明显降低睾丸组织u XBP-1/s XBP-1 mRNA的比值,以热处理后0.5和2 h最为显著,而随着时间的延长,又逐渐恢复正常。热应激明显诱导睾丸JNK(另一个IRE1的下游分子)磷酸化水平。结论单次热处理能激活睾丸组织内质网应激IRE1通路,在早期可能激活IRE1-XBP-1通路保护睾丸组织对抗热应激,而后期可能通过激活IRE1-JNK通路诱导睾丸生殖细胞凋亡。
Objective To investigate the role of endoplasmic reticulum stress IRE1 signaling pathway in inducing apoptosis of testicular germ cells in acute heat stress. Methods Twenty-four adult ICR male mice were randomly divided into four groups. The lower 1/3 part of the body of heat-treated mice (including the scrotum, hind legs and tail) was immersed in a constant temperature water bath at 43 ℃ for 15 min. The testicular tissues were taken at 0.5, 2 and 6 h after heat treatment. The control group mice were immersed in the lower abdomen of 22 ℃ water bath for 15 min, 6 h after the testicular group was taken. The apoptosis of testis germ cells was detected by TUNEL method. The expression of XBP-1 / XBP-1 mRNA was detected by semi-quantitative RT-PCR. The expression of p-JNK in testis was detected by Western blot. Results Single heat stress can significantly induce germ cell apoptosis in testis of mice. Compared with the control group, heat treatment could significantly reduce the ratio of uBP-1 / s XBP-1 mRNA in the testis, which was the most significant at 0.5 and 2 h after heat treatment, and gradually returned to normal with time. Heat stress significantly induces the phosphorylation of testicular JNK, another downstream molecule of IRE1. Conclusion Single heat treatment can activate IRE1 pathway in testis tissue and activate IRE1-XBP-1 pathway in the early stage to protect testicular tissue against heat stress. In the latter stage, IRE1-JNK pathway may induce testicular germ cell apoptosis.