睾酮抑制大鼠血管平滑肌细胞表型转化和增殖

Testosterone suppresses rat vascular smooth muscle cell phenotypic transition and proliferation

目的：研究睾酮对氧化型低密度脂蛋白（ ox-LDL）诱导大鼠血管平滑肌细胞（ VSMCs）表型转化和增殖的抑制作用,并探讨其可能机制。方法培养大鼠VSMCs,将细胞分为对照组、ox-LDL组（50μg/ml）、血清组（10%胎牛血清）、睾酮组（5＆#215;10-8或5＆#215;10-7mol/L睾酮加50μg/ml ox-LDL）。水溶性四甲基偶氮唑盐（WST-1）法检测各组细胞增殖的变化；流式细胞仪检测各组细胞周期的变化；Western印迹法检测各组细胞线粒体融合素2蛋白（Mfn2）、磷酸化细胞外信号调节激酶1/2蛋白（p-ERK1/2）、增殖细胞核抗原（ PCNA）、α-平滑肌肌动蛋白（α-SMA）及骨桥蛋白（ OPN）表达水平。结果与对照组比较,ox-LDL组细胞增殖能力增强（P〈0.05）,G0/G1期细胞比例降低（P〈0.05）,S期细胞比例增加（P〈0.05）,Mfn2和α-SMA蛋白表达降低（P〈0.05）,p-ERK1/2、PCNA、OPN表达增加（P〈0.05）。与ox-LDL组比较,不同浓度睾酮组细胞增殖受抑制（P〈0.05）,G0/G1期细胞比例增加（P〈0.05）,S期细胞比例降低（P〈0.05）,Mfn2和α-SMA表达增加（P〈0.05）,p-ERK1/2、PCNA和OPN表达降低（P〈0.05）。结论睾酮抑制ox-LDL诱导的大鼠VSMCs表型转化及增殖,可能与其上调Mfn2、抑制ERK1/2信号通路有关。

Objective To investigate the inhibitory effect of testosterone on oxidized low-density lipoproteins （ ox-LDL）-stimulated phenotypic transition and proliferation of vascular smooth muscle cells （ VSMCs） in vitro, and to explore its possible mechanisms. Methods Rat VSMCs cultured in vitro were divided into control group, ox-LDL group（50μg/mlox-LDL）,fetalbovineserum（FBS）group（10% FBS）,andtestosteronegroups（5＆#215;10-8 or5＆#215;10-7 mol/L testosterone plus 50μg/ml ox-LDL） . The effect of testosterone on ox-LDL-induced proliferation of VSMCs was explored by WST-1 assay. The cell cycle distribution was determined using flow cytometry. Western blotting was used todetecttheexpressionsofmitofusin2（Mfn2）,phosphorylatedextracellularsignal-regulatedkinases1/2（p-ERK1/2） , proliferating cell nuclear antigen （ PCNA） ,α-smooth muscle actin （α-SMA） ,and osteopontin （ OPN） . Results Compared with control group, the proliferation of VSMCs was promoted by ox-LDL, the number of VSMCs decreased in G0/G1 phase and increased in S phase significantly, the expression levels of Mfn2 and α-SMA were significantly reduced, and the expression levels of p-ERK1/2, PCNA, and OPN were significantly raised in ox-LDL group. Compared with ox-LDL group, the proliferation of VSMCs was inhibited, the number of VSMCs increased in G0/G1 phase and decreased in S phase in two testosterone groups, along with the increased expressions of Mfn2 andα-SMA, and the descended expressions of p-ERK1/2, PCNA, and OPN. Conclusions Testosterone inhibits phenotypic transition and proliferation of VSMCs induced by ox-LDL in vitro, which may be related to the up-regulated expression of Mfn 2 and the suppression of ERK1/2 pathway.