miR-145对血管平滑肌细胞生物活性及SM22α mRNA表达的作用*

目的：探究miR-145 对血管平滑肌细胞（VSMC）的生物活性及对SM22α mRNA 表达的作用。方法： VSMC分为3 组，增殖VSMC组（ 增殖组）、增殖VSMC + 转染miR-145-NC 组（ 空载体组）、增殖VSMC+转染 miR-145 组（ 增殖转染组）。采用RT-PCR 检测VSMC中SM22α mRNA、miR-145 的表达；免疫印迹检测cyclin E、p27 蛋白水平；Transwell 小室检测VSMC侵袭能力；MTT检测VSMC活力；流式细胞术检测VSMC凋亡率。 结果：增殖组VSMC中SM22α mRNA、miR-145 水平与空载体组相比数值较为接近；与增殖组及空载体组相比， 增殖转染组VSMC中miR-145、SM22α mRNA 表达升高。增殖组VSMC中cyclin E、p27 蛋白水平与空载体组相 比无差异；增殖转染组cyclin E 蛋白水平低于空载体组、增殖组，p27 蛋白水平高于空载体组、增殖组。增殖组 VSMC迁移数量与空载体组相比无差异；增殖转染组VSMC迁移数量明显低于空载体组、增殖组。增殖组与空载 体组VSMC在不同时间点的OD 值均较为接近；增殖转染组OD 值在不同时间点均低于空载体组、增殖组。增殖 组VSMC凋亡率与空载体组数值接近，组间比较差距较小；增殖转染组VSMC凋亡率较空载体组和增殖组升高。 结论：过表达miR-145 通过促进SM22α 水平增加，抑制血管平滑肌细胞的增殖，并促进其凋亡。

Effect of miR-145 on the biological activity and SM22α mRNA expression of vascular smooth muscle cells

Objective To explore the effect of miR-145 on the biological activity of vascular smooth muscle cells （VSMC） and SM22α mRNA expression. Methods VSMCs were divided into three groups， proliferation VSMC group （proliferation group）， a proliferation VSMC+transfection miR-145-NC group （empty vector group）， a proliferation VSMC+transfection miR-145 group（ proliferation and transfection group）. RT-PCR was used to detect the expression of SM22α mRNA and miR-145 in VSMC. Western blotting was used to detect cyclin E and p27 protein levels. Transwell chamber was used to detect the invasion ability of VSMC ；MTT was used to detect the vitality of VSMC ； flow cytometry was used to detect the apoptosis rate of VSMC. Results The levels of SM22α mRNA and miR-145 in VSMCs in the proliferation group were closer to those in the empty vector group. Compared with the proliferation group and the empty vector group， the expression of miR-145 and SM22α mRNA in the VSMC of the proliferation transfection group increased. There was no difference in the levels of cyclin E and p27 protein in the VSMC between the proliferation group and the empty vector group. The cyclin E protein level in the proliferation transfection group was lower than that in the empty vector group and the proliferation group， and the p27 protein level was higher than that in the empty vector group and the proliferation group. There was no difference in the number of VSMC migration between the proliferation group and the empty vector group. The number of VSMC migration in the proliferation and transfection group was significantly lower than that in the empty vector group and the proliferation group. The OD values of VSMCs in the proliferation group and the empty vector group at different time points were relatively close. The OD value in the proliferation and transfection group was lower than that in the empty vector group and the proliferation group at different time points. The apoptosis rate of VSMC in the proliferation group was close to that in the empty vector group， and the difference between the groups was smaller ； the apoptosis rate of VSMCin the proliferation and transfection group was higher than that in the empty vector group and the proliferation group. Conclusion Overexpression of miR-145 can inhibit the proliferation of VSMC and promote their apoptosis by promoting the increase of SM22α levels.