雌激素受体对血管平滑肌细胞早衰的影响

Effects of the estrogen receptor on stress-induced premature senescence of vascular smooth muscle cells in vitro

目的探讨雌激素受体对血管平滑肌细胞(VSMCS)早衰的影响及其机制。方法体外培养的第2～3代雌性SD大鼠VSMCS分为实验组和对照组,在有或无不同浓度(10-10mol/L～10-8 mol/L)雌激素受体激动剂(PPT/DPN)存在时,用150μmol/L H2O2诱导早衰。采用流式细胞术检测衰老相关标志物(DcR2)、Pull down as-say,Western blotting等方法检测原癌基因Ras的表达或活性。结果流式细胞术检测显示,H2O2组血管平滑肌细胞DcR2表达率显著增高(P﹤0.05)。H2O2+PPT及H2O2+DPN各浓度组血管平滑肌细胞DcR2表达率均低于H2O2组,且随激动剂浓度增高而降低,但不同激动剂之间无显著差别(P﹥0.05)。H2O2组细胞内GTP-Ras/Total Ras比值显著高于对照组(P﹤0.05),在有10-8 mol/L PPT或DPN存在时,细胞内的GTP-Ras/Total Ras比值明显降低,但仍高于对照组。H2O2+PPT组和H2O2+DPN组之间差异无统计学意义(P﹥0.05)。结论在介导雌激素的抗早衰效应上,雌激素受体a(ERa)和雌激素受体b(ERb)可能具有同等效应;雌激素抗早衰效应机制之一可能是抑制原癌基因Ras的激活。

Objective To explore the effects and mechanism of the estrogen receptor on stress-induced premature senescence of vascular smooth muscle cells（VSMCS）.Methods The VSMCS,cultured from female SD rats and followed by 2-3 vitro passages,were induced into senescence by exposure to 150 μmol/L H2O2 in the presence or absence of different concentrations（10-10mol/L-10-8mol/L） of PPT/DPN.Expressions of senescence associated marker（DcR2） were detected by flow cytometry.Expressions or activities of the proto-oncogene Ras were detected by pull-down assay and Western blotting analysis.Results Flow cytometry analysis showed that in physiological concentrations,the estrogen receptor agonist significantly inhibited H2O2-promoted high-level expression of DcR2 of VSMCS in a dose-dependent manner（P﹤0.05）.Pull-down assay and Western blotting analysis revealed that administration of（10-10mol/L-10-8mol/L） of PPT/DPN obviously reduced the H2O2-induced activity of Ras（P﹤0.05）.Conclusion The estrogen receptor exerts inhibitive effect on stress-induced senescence of VSMCS by suppressing activity of Ras.ERa and ERb may have the same effects on stress-induced premature senescence of vascular smooth muscle cells in vitro.