目的 探讨衰老对睾丸间质细胞的形态及功能的影响.方法 青年(3月龄)及老年(24月龄)清洁级雄性SD大鼠各10只,麻醉后取血清检测总睾酮浓度,取睾丸组织用HE染色观察睾丸组织形态学变化,并用电镜观察睾丸间质细胞的超微结构改变.通过密度梯度离心分离原代睾丸间质细胞,并用LH刺激睾酮分泌后用Western blot比较青年组和老年组睾丸间质细胞类固醇合成快速调节蛋白(steroidogenic acute regulatory protein,StAR)表达水平的差异,并用ELISA法检测其睾酮分泌的差异.结果 HE染色显示老年大鼠睾丸呈老年退行性改变,电镜下观察到老年大鼠睾丸间质细胞线粒体水肿,线粒体嵴消失.老年大鼠血清睾酮水平显著低于青年组(P＜ 0.05).原代培养的睾丸间质细胞无论LH刺激与否,老年组细胞上清中睾酮浓度及StAR蛋白表达水平均显著低于青年组(LH刺激时P＜0.01,无LH刺激时P＜0.05).结论 衰老造成的睾丸间质细胞线粒体水肿及LH诱导的StAR蛋白表达水平下降与其睾酮合成能力降低密切相关.%Objective To study the morphological and functional of aged Leydig cells. Methods Ten young (3 months) and ten aged (24 months old) male SD rats of clean grade were used in the study as a research model. After anesthesia, blood samples were collected by vena cava puncture, and serum total testosterone concentrations were measured by ELISA. Histological changes of testis and ultrastructure changes of Leydig cells were observed by HE staining and electron microscopy (EM) respectively. Leydig cells were isolated from rat testes by density gradient centrifugation. After luteinizing hormone (LH) stimulation, the level of testosterone in cell culture supernatant was measured by ELISA and the expression of steroidogenic acute regulatory (StAR) in Leydig cells was detected by western blot. Results Degenerative changes were showed in aged rat testes by HE staining, and many swollen mitochondria with mitochondrial cristae disappeared were found in Leydig cells of aged rats by EM. The serum testosterone level of aged rats was significantly lower than that of young group (P<0.05). In primary Leydig cells, with or without LH stimulation, the supernatant testosterone level and StAR protein expression in aged group was significantly lower than that of young group (P<0.0l and P<0.05 respectively). Conclusion Mitochondrial swelling and low expression of LH-induced StAR protein might impaire the ability of testosterone synthesis in aged Leydig cells.
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