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目的研究携带TGF-βRⅡ胞外区基因的重组腺病毒pAd-sTGF-βRⅡ对大鼠心肌梗死(Myocardial infarction,MI)后心室重塑的影响,并探讨其可能的机制。方法结扎SD大鼠左冠状动脉前降支,建立大鼠MI模型,将模型大鼠随机分为MI组(生理盐水)、pAd-sTGF-βRⅡ组(pAd-sTGF-βRⅡ病毒上清液)、空载体组(pAdTrack),并另设假手术组。4周后,取冰冻切片,荧光显微镜下观察sTGF-βRⅡ在大鼠心肌组织中的表达;HE染色观察心肌组织结构;天狼猩红-饱和苦味酸染色法检测Ⅰ、Ⅲ型胶原的表达;免疫组化法检测α-平滑肌肌动蛋白(α-SMA)、基质金属蛋白酶-9(MMP-9)蛋白的表达;RT-PCR法检测凋亡相关基因bax、bcl-2 mRNA的表达。结果与MI组比较,pAd-sTGF-βRⅡ组大鼠心肌组织总Ⅰ、Ⅲ型胶原、MMP-9蛋白和bax基因mRNA的表达水平均明显降低(P<0.01),α-SMA阳性细胞数亦明显减少,bcl-2基因mRNA表达水平增加(P<0.01)。与假手术组比较,pAd-sTGF-βRⅡ组大鼠心肌组织总Ⅰ、Ⅲ型胶原、MMP-9蛋白和bax基因mRNA的表达水平明显升高(P<0.01),bcl-2基因mRNA的表达水平无明显差异(P>0.05)。结论重组腺病毒pAd-sTGF-βRⅡ干预可改善大鼠MI后心室重塑,其机制可能是通过抑制TGF-β介导的心肌纤维化和心肌细胞凋亡实现的。
Objective To investigate the effect of recombinant adenovirus pAd-sTGF-βRⅡ carrying extracellular domain of TGF-βRⅡ on ventricular remodeling after myocardial infarction (MI) in rats and its possible mechanism. Methods The left anterior descending coronary artery of SD rats was ligated to establish the MI model of rats. The rats were randomly divided into MI group (saline), pAd-sTGF-βRⅡ group (pAd-sTGF-βRⅡ virus supernatant) Empty vector group (pAdTrack), and another set of sham operation group. After 4 weeks, the frozen section was taken and the expression of sTGF-βRⅡ in rat myocardium was observed under a fluorescence microscope. The myocardial tissue was observed by HE staining. The expression of collagen type Ⅰ and Ⅲ was detected by Sirius scarlet-saturated picric acid staining. The expression of α-smooth muscle actin (α-SMA) and matrix metalloproteinase-9 (MMP-9) protein was detected by histochemistry. The expressions of bax and bcl-2 mRNA were detected by RT- Results Compared with the MI group, the mRNA expression of total collagen type Ⅰ, type Ⅲ collagen, MMP-9 and bax in the pAd-sTGF-βRⅡ group was significantly decreased (P <0.01). The number of α-SMA positive cells The mRNA expression of bcl-2 gene was significantly decreased (P <0.01). Compared with sham operation group, the expression of total Ⅰ, Ⅲ, MMP-9 and bax gene mRNA in myocardium of pAd-sTGF-βRⅡgroup was significantly increased (P <0.01), and the expression of bcl-2 mRNA No significant difference (P> 0.05). Conclusion The intervention of recombinant adenovirus pAd-sTGF-βRII can improve the ventricular remodeling after MI in rats, which may be through the inhibition of TGF-β-mediated myocardial fibrosis and cardiomyocyte apoptosis.