增龄对大鼠睾丸自噬水平和血睾屏障完整性的影响

Effects of aging on testicular autophagy and integrity of blood-testis barrier in rats

目的探究增龄过程中大鼠睾丸自噬水平的变化及其对血睾屏障的影响。方法HE染色法观察6、12、18和24月龄SD♂大鼠睾丸组织形态学的变化。Western blot法检测各组大鼠睾丸自噬相关蛋白Beclin1、ATG5、ATG7和LC3Ⅱ,以及血睾屏障相关蛋白Occludin和β-catenin的表达水平变化。免疫荧光法检测睾丸自噬相关蛋白Beclin1和LC3,以及血睾屏障相关蛋白β-catenin的蛋白表达及定位。结果HE染色观察发现,增龄过程中大鼠睾丸组织形态结构发生明显变化,生精小管萎缩,生精细胞层数减少,细胞间间隙增大,且发生部分脱落现象;Western blot结果显示,增龄过程中大鼠睾丸自噬相关蛋白Beclin1、ATG5、ATG7和LC3Ⅱ,以及Occludin和β-catenin表达水平均逐渐下降;免疫荧光结果显示,增龄过程中大鼠睾丸生精小管上皮细胞中Beclin1和LC3蛋白表达逐渐下调,并且血睾屏障标志蛋白β-catenin表达也逐渐下降。结论增龄过程中大鼠睾丸生精功能减退,其机制与睾丸生精上皮细胞自噬水平下降,进而破坏血睾屏障的完整性有关。

Aim To investigate the changes of autophagy in rat testis and its effect on blood-testis barrier during aging.Methods HE staining was used to observe the morphological changes of testis in SD male rats at 6,12,18 and 24 months old.Western blot was used to detect the relative expression of autophagy-related proteins Beclin1,ATG5,ATG7 and LC3II,and the blood-testis barrier related connexins Occludin andβ-catenin.Immunofluorescence was used to detect the expression and localization of the autophagy-associated proteins Beclin1 and LC3,as well as the protein of the cell connexinβ-catenin.Results HE staining showed that the morphology and structure of rat testis changed significantly during the aging process,the seminiferous tubules atrophied,the number of spermatogenic cells decreased,the gap between cells increased,and partial shedding occurred.Western blot results showed that the relative expression of autophagy-related proteins Beclin1,ATG5,ATG7 and LC3II,and the blood-testis barrier-related proteins Occludin andβ-catenin gradually decreased during aging.The results of immunofluorescence showed that the autophagy marker proteins Beclin1 and LC3 were down-regulated in rat seminiferous epithelial cells during the aging process,and the expression of the blood-testis barrier marker proteinβ-catenin also gradually decreased.Conclusions During the aging process,the spermatogenic function of the testis is reduced in rats,and the mechanism is related to the decrease of the autophagy level of testicular spermatogenic epithelial cells,which in turn destroys the integrity of the blood testis barrier.