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(5×10-8 or5×10-7 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.

[摘 要] 目的：探讨大荨麻提取物对乳腺癌细胞增殖、凋亡和细胞周期的影响，并初步探讨其可能的作用机制。方法：用不同质量浓度的大荨麻提取物（0、1、2、4、8、16、32、64 mg/ml）处理乳腺癌细胞MCF-7和MDA-MB-231 24 h，MTT法检测细胞增殖活力，选择中位抑制浓度附近的浓度（5和10 mg/ml）作为给药浓度分别处理MCF-7和MDA-MB-231细胞24 h后，平板克隆形成实验和流式细胞术分别检测大荨麻提取物对乳腺癌细胞增殖、周期和凋亡的影响，WB法检测对细胞周期和凋亡相关蛋白以及PI3K/AKT信号通路相关蛋白表达的影响。在MCF-7细胞用5 mg/ml大荨麻提取物处理的同时转染过表达AKT质粒（大荨麻+AKT组），转染空载质粒为对照组（大荨麻+vec组），WB法检测过表达效率，比较过表达AKT对细胞增殖、周期和凋亡的影响。结果：各大荨麻提取物处理组MCF-7和MDA-MB-231细胞增殖活力均显著低于对照组（P<0.05或P<0.01）；与对照组比较，5或10 mg/ml大荨麻处理组乳腺癌细胞的克隆形成数显著减少，G0/G1期细胞占比和凋亡率显著增加（P<0.05或P<0.01），P21、BAX蛋白表达显著升高而Cyclin D1、CDK4、Bcl2蛋白以及p-PI3K、p-AKT蛋白表达显著降低（P<0.05或P<0.01）。大荨麻+AKT组p-AKT和AKT蛋白表达显著高于大荨麻+vec组，克隆数、S期和G2/M期细胞占比均高于大荨麻+vec组（P<0.05或P<0.01），G0/G1期细胞占比和凋亡率低于大荨麻+vec组（P<0.05或P<0.01）。结论：大荨麻提取物可以抑制乳腺癌细胞增殖、促进凋亡且阻滞细胞在G0/G1期，其作用机制可能与抑制PI3K/AKT信号通路相关。