雌激素具有抗血管平滑肌细胞应激性衰老效应

Estrogen exerts the effect on stress-induced senescence of vascular smooth muscl cells in vitro

目的探讨雌激素对血管平滑肌细胞（VSMCs）应激性衰老的影响及其机制。方法体外培养的第2~3代雌性SD大鼠VSMCs在无或有不同浓度（10-10mol/L^10-8mol/L）17β-雌二醇（E2）存在时,用150μmol/L H2O2诱导应激性衰老。流式细胞术、细胞化学染色P、ull down assay和Western blotting等检测衰老相关标志DcR2、衰老相关β-半乳糖苷酶（SA--βGal）、原癌基因Ras及细胞周期负性调控因子p21WAF1的表达或活性。结果流式细胞术显示,在生理浓度范围内,E2呈剂量依赖性地抑制H2O2诱导的VSMCs DcR2高表达、其中最大抑制作用达14.48%±0.6%（E2=10-8mol/L;P＆lt;0.05,n=3）,且这一效应可被雌激素受体阻断剂ICI 182、780阻断。细胞化学染色、Pulldown和Western blotting检测显示,10-8mol/L E2可显著性地抑制H2O2所致的SA--βGal阳性VSMCs上升（20.5%±1.4%和9.6%±0.9%;P＆lt;0.05,n=9）、Ras活性增高（0.60±0.06和0.26±0.04;P＆lt;0.0...

Objective To explore the effects of estrogen on stress-induced senescence of vascular smooth muscle cells （VSMCs） and the underlying mechanisms. Methods The VSMCs of passage 2-3 cultured from female SD rats were induced into senescence by exposing to 150μmol/L H2O2 in the presence or absence of different concentrations（ 10-10 mol/L-10-8 mol/L） of 17β- estradiol （E2）. The expressions or activities of senescence associated marker DcR2, senescence-associated beta-galactosidase （SA-β-Gal）, oncogene Ras and P21WAFI were detected by flow cytometry, cytochemical staining, pull-down assay or Western blotting analysis. Results Flow cytometry analysis showed that in the physiological concentrations, E2 significantly inhibited the H2 O2-promoted high-level expression of DcR2 of VSMCs in a dose-dependent manner, with a highest inhibitive rate at 14.48 % ± 0.6%（E2 = 10-8 mol/L; P 〈 0.05, n = 3）; this inhibitive effect could be blocked by a E2 receptors inhibitor ICI 182,780. Cytochemistry staining showed that the rate of SA-β-Gal positive VSMCs induced by H2O5 decreased in presence of 10-8 mol/L E2 （20.5% ± 1.4% vs 9.6% ± 0.9%; P 〈 0.05, n = 9）. Pall-down assay and Western blotting analysis revealed that administration of 10-Smol/L E2 obviously reduced the H2O2-induced activity of Ras （0.60 ± 0.06 vs 0.26 ± 0.04; P 〈 0.05, n =3） and expression of p21WAFI （0.46 ± 0.04 vs0.33±0.02; P〈0,05, n=3）. Conclusion E2 exerts, an inhibitive effects on stxess-induced senescence of VSMCs by suppressing the activity of Ras and expression of p21WAFI . This finding suggests a novel mechanism for the hormone＇s anti-atheroschlerotic effects.