局部高温对青春期前大鼠睾丸支持细胞波形蛋白的影响及其与生精细胞凋亡的关系

目的:探讨局部高温对青春期前大鼠睾丸支持细胞波形蛋白表达和分布的影响及其与生精细胞凋亡的关系。方法:选取青春期前SD大鼠40只,随机分为对照组8只和实验组32只,实验组按热处理后2、4、12、24h均分成4个亚组;通过对睾丸局部高温(43℃水浴15min)处理,对照组以22℃水浴15min处理,采用组织化学和免疫组化方法,分析高温对青春期前大鼠生精小管细胞形态结构、支持细胞波形蛋白表达与分布的影响,采用TUNEL法检测各组生精细胞凋亡情况。结果:与对照组比较,高温处理后2h及4h即可见生精细胞与支持细胞发生分离,且自基膜脱落至管腔,数目逐渐增多;免疫组化发现,对照组波形蛋白沿基膜形成环样并随支持细胞胞质向管腔伸展分布,2h组波形蛋白围绕支持细胞核周分布,伸至管腔的蛋白表达减少或消失,其表达量与对照组比较无差别,12h及24h组与对照组比较差异有显著性(P<0.01);凋亡检测表明,12h及24h组生精细胞凋亡明显增加,而2h及4h组生精细胞凋亡与对照组比较反而减少。结论:高温可导致支持细胞波形蛋白的表达增多及分布变化,其改变与生精细胞凋亡有密切关系,高温可能通过直接作用于支持细胞而破坏生精过程。

Relationship Between Germ Cell Apoptosis and Sertoli Cell Vimentin in Prepubertal Rats Induced by Local Exposure to Heat

OBJECTIVE: To explore the relationship between germ cell apoptosis and the expression as well as the distribution of Sertoli cell vimentin induced by local exposure to heat. METHODS: Local short-term exposure of prepubertal male rats testis to heat (43 degrees C for 15 min). Histochemical method was used to observe morphological characteristics of seminiferous tubule. The distribution and expression of Sertoli cell cytoskeletons were analyzed by immunohistochemistry and germ cell apoptosis was evaluated by TUNEL technique at different hour-intervals. RESULTS: After 2 h and 4 h heat exposure, the disattachment phenomenon between Sertoli cell and spermatogonia occurred. Spermatogonia arranged in disorder and displaced away from the basement membrane of seminiferous tubules. Immunohistochemical staining showed that vimentin positive staining was seen radiating from the Sertoli cell perinuclear region with apical "spoke-like" pattern in controls. There was an intense vimentin immunoreactivity surrounding Sertoli cell nuclei along with the collapse of the apical extensions in 2 h group, but no significant difference compared with the controls. The expressions of vimentin in 12 h and 24 h groups were higher than those of the controls (P <0.01), respectively. TUNEL showed that incidence of apoptosis was observed to increases markedly in 12 h and 24 h groups, but it was found that the incidences of apoptotic events were decreased in these two groups compared with the controls. CONCLUSION: The changes of expression and distribution of Sertoli cell vimentin filaments correlate with the increased germ cell apoptosis. Local heat may disrupt spermatogenesis by injuring Sertoli cell directly.