AT2R基因转染对大鼠颈动脉球囊损伤后BTEB2表达的影响

Effect of AT2R gene transfer on BTEB2 expression in rat carotid ateries after balloon angioplasty

目的研究AngⅡ2型受体(angiotensinⅡtype 2 receptor,AT2R)基因转染对大鼠颈动脉球囊损伤后基本转录元件结合蛋白2(basic transcription elem ent b ind ing prote in 2,BTEB2)表达变化的影响,揭示AT2R介导抑制新生内膜形成作用的机制。方法大鼠颈动脉球囊损伤后,局部转染带有大鼠AT2R基因的重组腺病毒载体(pAdCMV/AT2R)或空病毒载体(pAd-GFP),分为正常组、未转染组、pAd-GFP组、pAdCMV/AT2R组。于术后7、14、21 d取材,用HE染色、图像分析、逆转录-聚合酶链反应、免疫组织化学方法检测AT2R、BTEB2 mRNA及蛋白水平在大鼠颈动脉壁中的表达及新生内膜增生变化。结果在正常组无AT2R、BTEB2 mRNA及蛋白表达;在球囊损伤的未转染组和pAd-GFP组AT2R、BTEB2mRNA及蛋白表达显著高于正常组;在pAdCMV/AT2R组,AT2R的表达水平显著高于未转染组和pAd-GFP组(P<0.01),大鼠颈动脉内膜/中膜面积比(I/M)显著低于未转染组和pAd-GFP组(P<0.01),BTEB2 mRNA及蛋白表达显著低于未转染组和pAd-GFP组(P<0.01)。结论AT2R基因转染能抑制新生内膜形成,能显著下调BTEB2的表达,提示BTEB2的下调表达参与了AT2R介导的抑制新生内膜形成作用的机制。

Objective To study the effect of angiotensin Ⅱ type 2 receptor （AT2R） gene transfer on BTEB2 expression in rat carotid arteries after balloon angioplasty and explore the mechanism of AT2R-mediated inhibition of neointimal hyperplasia. Methods Following the establishment of rat carotid restenosis model after balloon injury, pAdCMV/AT2R with AT2R gene or control virus pAd-GFP was transduced into rat carotid arteries. Rats were assigned into normal group, non-transduced group, pAd-GFP group, pAdCMV/AT2R group. The arteries were harvested on day 7, 14, 21 after gene transfer. The expressions of AT2R, BTEB2 and the change of neointima were evaluated by RT-PCR, immunohistochemistry, HE and image analysis. Results The expressions of AT2R and BTEB2 were negative in normal group. After balloon injury, the expressions of AT2R, BTEB2 in vessels increased significantly. In pAdCMV/AT2R group, the levels of AT2R in vessels were much higher, but the levels of BTEB2 as well as the ratio of new intima to media area were significantly lower than that of non-transduced and pAd-GFP group （ both P 〈 0. 01 ）. Conclusion AT2R gene transfer inhibits neointimal hyperplasia and BTEB2 expression in rat carotid artery after balloon injury. The low expression of BTEB2 may involve in the mechanism of AT2R-meidated inhibition of neointimal hyperplasia.