睾酮对去势大鼠血管平滑肌细胞线粒体损伤的影响

Protective effect of testosterone on mitochondrial damage of vascular smooth muscle cells of castrate rats

目的研究生理剂量睾酮对去势大鼠主动脉血管平滑肌细胞线粒体损伤的保护作用,并探讨其可能机制。方法选取8周龄雄性SD大鼠30只,随机分为假手术组,去势组和去势+睾酮组,每组10只。去势组行睾丸切除术,去势+睾酮组在去势后每天给予丙酸睾酮5.0 mg/kg肌肉注射。12周后测定各组血清睾酮浓度,并取大鼠胸主动脉,免疫印迹法检测血管平滑肌组织线粒体融合素2蛋白表达,激光共聚焦显微镜观察线粒体形态变化;JC-1检测线粒体膜电位;测定细胞总三磷酸腺苷(ATP)含量,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性以及丙二醛(MDA)水平。结果与假手术组比较,去势组大鼠血清睾酮水平降低(P<0.05),线粒体融合素2表达降低(P<0.05),线粒体聚集呈团块状,线粒体膜电位减低(P<0.05),ATP含量、SOD和GSH-Px活性降低(P<0.05),MDA水平增加(P<0.05)。与去势组相比,去势+睾酮组大鼠血清睾酮水平升高(P<0.05),线粒体融合素2表达增加(P<0.05),线粒体呈管状分布,线粒体膜电位增高(P<0.05),ATP含量、SOD和GSH-Px活性增加(P<0.05),MDA水平降低(P<0.05),与假手术组比较差异无统计学意义(P>0.05)。结论生理剂量睾酮可维持去势大鼠血管平滑肌细胞的线粒体形态和膜电位水平,增加细胞ATP含量,降低氧化应激水平,对线粒体损伤具有保护作用,上调线粒体融合素2表达是其可能机制之一。

Objective To investigate the protective effect of testosterone on the mitochondrial damage of vascular smooth muscle cells of castrated rats,and to explore its possible mechanisms. Methods A total of 30 male Sprague-Dawley（ SD） rats were randomly divided into sham- operated group,castrated group（ treated with normal saline）,and castrated ＋ testosterone group（ treated with testosterone 5. 0mg / kg daily）. After treatment for 12 weeks,the rats were sacrificed,and blood samples were drawn for measurement of plasma testosterone. The expression of Mitofusin 2（ Mfn2） was detected by western blotting. The mitochondrial morphology and distribution was observed through laser confocal microscopy. The mitochondrial membrane potential（ ΔΨm） was detected by JC- 1 staining method. The total contents of ATP,superoxide dismutase（ SOD）,glutathione peroxidase（ GSH- Px）,and malondialdehyde（ MDA） were determined by assay kits. Results Compared with the sham group,the plasma testosterone level and Mfn2 protein expression in castrated group were significantly reduced（ P〈0. 05）; so were the ΔΨm,and the total contents of ATP,SOD,and GSH- Px;while the MDA was significantly increased（ P〈0. 05）. Mitochondrial fusion and morphology was dramatically altered in castrated group. Compared with the castrated group,significant increase in the plasma testosterone level,Mfn2 protein expression,ΔΨm,and the total contents of ATP,SOD,and GSH- Px in castrated ＋ testosterone group（ P〈0. 05）; so was the reduction in MDA level（ P〈0. 05）. No significant difference in mitochondrial morphology or distribution was observed between the sham and the castrated ＋ testosterone groups. Conclusion Testosterone at physiological concentration plays a protective role in the mitochondrial damage of vascular smooth muscle cells of castrated rats,which may relate to up- regulation of mitofusin 2.