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目的探讨腺病毒介导人受体活性修饰蛋白1(hRAMP1)基因转染间充质干细胞(MSC)移植对心肌梗死后心肌纤维化和心室重构的影响及可能机制。方法建立心肌梗死再灌注兔模型,随机分为hRAMP1组(高表达hRAMP1基因的MSC移植,n=10)、MSC组(无基因修饰的单纯MSC移植,n=10)和对照组(生理盐水注射,n=10)。Western blot检测心肌梗死后1、3、7和28d心肌梗死局部基质金属蛋白酶9(MMP-9)和hRAMP1蛋白表达水平;同时行2,3,5三苯基氯化四氮唑染色检测心肌梗死面积,心肌组织Masson染色评价心肌梗死后胶原沉积和纤维化程度;超声心动图评价28d时左心室舒张末期内径(LVEDD)、左心室收缩末期内径(LVESD)、左心室射血分数(LVEF)及短轴缩短率(FS)。结果细胞移植后,与对照和MSC组相比,hRAMP1组的LVEF[(57.2±6.3)%比(36.2±2.2)%、(45.3±5.4)%]和FS[(29.2±2.4)%比(13.5±1.4)%、(19.4±2.4)%]均升高(均P<0.05),而LVESD[(7.9±0.8)比(12.7±0.9)、(10.4±0.9)mm]和LVEDD[(12.7±1.2)比(17.3±2.4)、(16.3±1.1)mm]、心肌梗死面积、胶原容积分数均明显降低,胶原沉积减少。免疫印迹结果显示,hRAMP1组MMP-9蛋白表达较对照、MSC组明显增高。结论 hRAMP1移植通过促进梗死区心肌组织MMP-9表达,降低梗死区胶原沉积,抑制心肌纤维化,进而改善心室重构,提高心功能。
Objective To investigate the effect of hRAMP1-mediated transfection of mesenchymal stem cells (MSCs) on myocardial fibrosis and ventricular remodeling after myocardial infarction and its possible mechanism. Methods Rabbit models of myocardial infarction and reperfusion were established and randomly divided into three groups: hRAMP1 group (MSC transplantation with high expression of hRAMP1 gene, n = 10), MSC group (MSC transplantation without gene modification, n = 10) and control group , n = 10). Western blot was used to detect the expression of MMP-9 and hRAMP1 at 1, 3, 7 and 28 days after myocardial infarction; at the same time, 2,3,5-triphenyltetrazolium chloride was used to detect myocardial infarction Area and myocardium Masson staining to evaluate the degree of collagen deposition and fibrosis after myocardial infarction. The left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular ejection fraction (LVEF) Short axis shortening rate (FS). Results After LVEF [(57.2 ± 6.3)% vs (36.2 ± 2.2)%, (45.3 ± 5.4)%] and FS [(29.2 ± 2.4)% 13.5 ± 1.4% vs 19.4 ± 2.4%, respectively) (all P <0.05), while LVESD [(7.9 ± 0.8) vs (12.7 ± 0.9) ± 1.2), (17.3 ± 2.4) and (16.3 ± 1.1) mm respectively. The area of myocardial infarction and collagen volume were significantly decreased and collagen deposition was decreased. Immunoblotting results showed that MMP-9 protein expression in hRAMP1 group was significantly higher than that in control group, MSC group was significantly higher. Conclusion hRAMP1 transplantation can improve myocardial function by promoting MMP-9 expression in myocardial infarction area, reducing collagen deposition in infarction area, inhibiting myocardial fibrosis.