AIM:To investigate the effects of xeroderma pigmentosum group D ( XPD) gene on the prolifera-tion of human umbilical arterial smooth muscle cells ( HUASMCs) induced by oxidized low-density lipoprotein ( Ox-LDL) . METHODS:The recombinant plasmid pEGFP-N2/XPD was transfected into HUASMCs by liposome .The cells were di-vided into blank control group , pEGFP-N2 group, pEGFP-N2/XPD group, Ox-LDL group, Ox-LDL+pEGFP-N2 group and Ox-LDL+pEGFP-N2/XPD group.The proliferation rate of the cells was detected by MTT and EdU assays .The apop-totic rate and cell cycle distribution were analyzed by flow cytometry .The protein levels of XPD, caspase-3, Bcl-2 and Bax were determined by Western blot .RESULTS:Compared with blank control group , the expression of XPD was increased in pEGFP-N2/XPD group (P<0.05).According to the results of MTT and EdU assays , the cell proliferation in pEGFP-N2/XPD group was reduced compared with blank control group (P<0.05).Compared with Ox-LDL group, the cell prolifera-tion in Ox-LDL+pEGFP-N2/XPD group was significantly inhibited (P<0.05).According to the results of flow cytome-try, the cell proportion of S phase decreased and the G 0/G1-phase cell proportion increased significantly in pEGFP-N2/XPD group and Ox-LDL+pEGFP-N2/XPD group compared with blank control group and Ox-LDL group, repectively (P<0.05).Compared with blank control group and Ox-LDL group, the protein level of Bcl-2 decreased and the protein levels of Bax and cleaved caspase-3 increased in pEGFP-N2/XPD group and Ox-LDL +pEGFP-N2/XPD group, respectively (P<0.05).CONCLUSION:XPD inhibits the proliferation of HUASMCs and promotes their apoptosis , and reduces the promoting effect of Ox-LDL on the proliferation of HUVSMCs .XPD may be the target for treatment of atherosclerosis .%目的:探讨剪切修复基因——着色性干皮病D组基因(XPD)在氧化低密度脂蛋白(Ox-LDL)促血管平滑肌细胞增殖中的作用及机制.方法:将重组质粒pEGFP-N2/XPD利用脂质体转染人脐动脉平滑肌细胞(HUASMCs),实验分为空白对照组、空载质粒pEGFP-N2组、重组质粒pEGFP-N2/XPD组、Ox-LDL组、Ox-LDL+pEGFP-N2组和Ox-LDL+pEGFP-N2/XPD组.用MTT法和EdU法测定各组细胞的增殖率;流式细胞术检测各组细胞周期分布;利用Western blot法检测XPD、caspase-3、Bcl-2和Bax的蛋白水平.结果:Western blot实验结果发现,与空白对照组相比,pEGFP-N2/XPD组的XPD表达增加(P<0.05),表明转染成功;MTT和EdU检测结果显示,pEGFP-N2/XPD组的细胞增殖率较空白对照组降低(P<0.05);与Ox-LDL组比较,Ox-LDL+pEGFP-N2/XPD组细胞增殖明显被抑制(P<0.05).流式细胞术的检测结果显示,与空白对照组比较,pEGFP-N2/XPD组的S期细胞比例明显减少(P<0.05),G0/G1期细胞比例明显增多(P<0.05);与Ox-LDL组比较,Ox-LDL+pEGFP-N2/XPD组的S期细胞比例减少(P<0.05),G0/G1期细胞比例明显增多(P<0.05).Western blot结果显示,与对照组比较,pEGFP-N2/XPD组的cleaved caspase-3和Bax蛋白水平增加(P<0.05),Bcl-2蛋白表达降低(P<0.05);与Ox-LDL组比较,Ox-LDL+pEGFP-N2/XPD组的cleaved caspase-3和Bax蛋白水平增加(P<0.01),Bcl-2蛋白表达降低(P<0.05).结论:XPD能抑制HUASMCs的增殖并促其凋亡,还能抑制Ox-LDL的促HUASMCs增殖作用,有可能成为抗动脉粥样硬化治疗的靶点.
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