腹股沟区皮下埋藏睾丸对生精细胞凋亡及Bcl-2/Bax蛋白表达的影响

Spermatogenic cell apoptosis and expressions of Bcl-2 and Bax proteins after burying the testis in the inguinal pocket

目的:通过观察腹股沟区皮下埋藏睾丸生精细胞的凋亡及Bcl-2/Bax蛋白表达,探讨二者的关系。方法:以健康育龄期36只雄性新西兰大白兔为实验动物,随机分成实验组18只、对照组18只。实验组动物将双侧睾丸分别移位埋藏至双侧腹股沟区皮下,以制备睾丸埋藏修复阴囊皮肤缺损模型;对照组未作处理。动物模型建立后第8周末,每组随机取6只大白兔测量睾丸表面温度后进行睾丸活检。睾丸组织行原位末端标记(TUNEL)法检测生精细胞凋亡、免疫组化法结合图像分析仪检测睾丸生精细胞Bcl-2、Bax蛋白的表达。结果:对照组的睾丸表面温度为(36.15±0.64)℃,实验组为(38.02±0.36)℃,两组比较差异有统计学意义(P<0.05)。模型建立后第8周末实验组睾丸生精小管中生精细胞的凋亡指数(AI)为(89.69士3.76)%,对照组为(7.73±4.95)%,两者比较有显著差异(P<0.05)。实验组Bax表达显著升高(P<0.05),Bcl-2表达显著降低(P<0.05),凋亡细胞主要为初级精母细胞和圆形精子细胞。结论:腹股沟区皮下埋藏睾丸局部温度升高诱导睾丸的生精细胞凋亡增加,生精细胞凋亡增加与Bcl-2蛋白表达降低、Bax蛋白表达升高密切相关。Bcl-2/Bax的改变是高温引起生精细胞凋亡的机制之一。

Objective： To observe the apoptosis of spermatogenic cells and the expressions of Bcl-2 and Bax proteins after burying the testis in the inguinal pocket,and to investigate their relationship.Methods： We randomly divided 36 healthy male New Zealand white rabbits into an experimental group（n=18） and a control group（n=18）.Models were established by burying testes in the inguinal pocket in the experimental group,while the controls were left untreated.At the end of the 8th week after surgery,6 animals were randomly taken from each group for measurement of the testis surface temperature and testicular biopsy.The apoptosis of spermatogenic cells in the testis tissues was detected by TUNEL assay,and the expressions of Bcl-2 and Bax proteins determined by immunohistochemistry and imaging analysis.Results： At 8 weeks after burying the testis in the inguinal pocket,the testicular surface temperature was significantly higher in the experimental group than in the control（[38.02±0.36]℃ vs [36.15±0.64]℃,P0.05）,and so was the apoptosis index（AI） of spermatogenic cells（[89.69±3.76]% vs [7.73±4.95]%,P0.05）.The expression of the Bax protein in the testis was significantly increased,while that of the Bcl-2 protein remarkably decreased in the experimental group as compared with the control group（P0.05）.The apoptotic cells were mostly primary spermatocytes and round spermatids.Conclusion： Elevated local temperature of the testis buried in the inguinal pocket increases the apoptosis of spermatogenic cells,and the spermatogenic cell apoptosis is highly correlated with the decreased expression of Bcl-2 and increased expression of Bax.The changes in the expressions of Bcl-2 and Bax proteins were a main mechanism behind the temperature elevation-induced apoptosis of spermatogenic cells.