脉冲电场介导AT2R基因在血管局部表达及其对血管新生内膜的影响

Electroporation-mediated angiotensin Ⅱ type 2 receptor expression improves neointimal hyperplasia of carotid arteries in rats after balloon angioplasty

目的研究脉冲电场对血管紧张素2型受体(AT2R)基因在血管局部表达的作用,探讨AT2R基因在体转染对大鼠颈动脉球囊损伤后新生内膜增生的作用。方法大鼠颈动脉球囊损伤后,用脉冲电穿孔法介导AT2R cDNA真核表达质粒或空质粒载体在动脉局部表达,于术后3、7 d和21 d用免疫组织化学、HE染色等方法,进行AT2R在颈动脉壁中表达的变化及定量组织形态学分析。结果免疫组织化学染色结果显示:脉冲电场介导AT2R cDNA真核表达质粒表达后,3 d时可见内膜、中膜、外膜大量AT2R的棕色阳性着色,7 d时可见少量棕色阳性着色,21 d棕色阳性着色几乎消失,未转染组及空质粒转染组未见AT2R的棕色阳性着色,表明脉冲电穿孔能有效导入AT2R基因,并在动脉壁获得稳定表达。在21 d时,AT2R cDNA真核表达质粒组的内膜面积与中膜面积比显著低于未转染组和空质粒载体组[分别为(0.76±0.08)、(1.39±0.08)、(1.32±0.10),P<0.01],空质粒转染组和未转染组间无统计学差异(P>0.01)。结论脉冲电穿孔可介导AT2R基因在血管局部有效表达,AT2R在体转染可抑制球囊损伤后大鼠颈动脉平滑肌细胞增殖和新生内膜增生。

Objective To determine the effects of electroporation on the transfection of angiotensin Ⅱ type 2 receptor（AT2R） gene into rat carotid arteries and predict its role in neointimal hyperplasia of carotid arteries after balloon angioplasty.Methods After the establishment of rat carotid balloon injury restenosis model,18 SD rats were divided into AT2R transfection group,empty plasmid transfection group（GFP）,and non-transfection group（n=6）.AT2R gene plasmid or empty plasmid was transfected by electroporation into rat carotid arteries.Their arteries were harvested at 3,14 and 21 d after gene transfer,with 2 rats at each time points.The expression of AT2R and morphology of the arteries were evaluated by immunohistochemistry and HE staining respectively.Results Electroporation-mediated transfection of AT2R gene into injured rat carotid arteries significantly up-regulated the levels of AT2R mRNA in the neointima in a time dependent manner from day 3 to day 14（strong to moderate to mild expression）.But no expression of AT2R was found in the other 2 groups at these 3 time points.At day 21,AT2R transfection significantly reduced intimal/medial area ratio as compared with non-transfection group and GFP transfection group（0.76±0.08 vs 1.39±0.08 and 1.32±0.10,P0.01）.No significant difference was found between non-transfection group and GFP transfection group.Conclusion Our results indicate that electroporation is an effective means to introduce naked AT2R DNA into the blood vessel wall,and gene transfer of AT2R in vessel wall may effectively inhibit VSMC proliferation and neointimal hyperplasia in the rat carotid arteries after balloon angioplasty.