TIMP-3基因转染血管平滑肌细胞移植对大鼠急性心肌梗死后心脏结构的影响

目的研究基质金属蛋白酶组织抑制因子3（tissue inhibitor-3 of matrix metalloproteinases, TIMP- 3 ）基因转染血管平滑肌细胞（vascular smooth muscle cells,VSMCs）移植，对急性心肌梗死（acute myocardial infarction, AMI）后早期心脏结构变化的影响，并探讨其可能的机制。方法取Wistar大鼠胸主动脉采用组织块贴壁法培养VSMCs。另取54只Wistar雌性大鼠建立左冠状动脉远端结扎的AMI动物模型，随机分三组。冠状动脉结扎后立即向缺血部心室壁内注射含有1×10^6个TIMP-3基因转染VSMCs（A组），1×10^6个VSMCs（B组）或不舍细胞的DMEM液（C组），各0．5ml。术后3天，进行心脏形态学检测观察大鼠心脏结构变化，免疫组化染色验证TIMP-3基因转染VSMCs在缺血心肌中的存活情况，RT—PCR法测定大鼠缺血心肌TIMP-3和基质金属蛋白酶9（matrix metalloproteinase 9，MMP-9）mRNA含量。结果成功分离、培养VSMCs，纯度达98％，TIMP-3基因成功转入VSMCs中。术后3天，A组的左心室容积较正常鼠升高（P〈0．01），但小于B（P〈0．01）组和C组（P〈0．01），B组小于C组（P〈0．01）。A组的左心室客积指数较正常组有所上升（P〈0．01），但小于B和C组（P〈0．01）。免疫组化染色见TIMP-3基因转染VSMCs被成功植入缺血心肌并在其中存活。RT—PCR结果显示：各移植组TIMP-3mRNA含量均较对照组显著升高（P〈0．01），A组较B组、C组明显增高（P〈0．01），B组较C组增高（P〈0．01）；A组MMP-9mRNA含量较B组、C组明显降低（P〈0．01），B组较C组降低（P〈0．01）。结论将TIMP-3基因转染的VSMCs移植入心肌缺血区可明显抑制MMP-9的表达，进而抑制AMI后早期心肌重塑，改善心功能。

Effects of tissue inhibitor-3 of matrix metalloproteinases Gene-transfected vascular smooth muscle cells transplantation on initial myocardium function after acute myocardial structure

Objective To investigate the effects of tissue inhibitor -3 of matrix metalloproteinases （TIMP-3） Gene-transfected vascular smooth muscle cells （VSMCs） transplantation on heart function after acute myocardial infarction （AMI） in rats and to explore the potential mechanisms. Methods Female Wistar rats were produced AMI models by ligating the descending left coronary artery. Fifty- four rats were survived and divided into 3 groups randomly （n = 18） ： 0.5mlDMEM containing 1 × 10^6 TIMP-3 gene-transfected VSMCs（group A）, 1×10^6 VSMCs （group B） or 0.5 ml DMEM without cell（group C） were injected into the ischemic myocardium immediately. Ischemic myocardium samples were harvested at 3 days after operation. The heart function was observed through the tissue functional examination. The activity of TIMP-3 gene-transfected VSMCs were measured by immunohistochemical method, mRNA of TIMP-3 and matrix metalloproteinase 9 （MMP-9） were determined by RT-PCR. Results VSMCs were cultivated and had a high purity （98%）. TIMP-3 gene was transfected into VSMCs successfully. Three day after operation in group A the average percentage of left ventricular volume was significantly higher than group normal （P 〈 0.01）, but was lower than group B and group C （P 〈 0.01）, in group A the average percentage of index of left ventricular volume was higher than group normal （P〈0.01）, but smaller than group B and group C （P〈0.01）. The immunohistochemical observation confirmed that the implanted VSMCs and TIMP- 3 gene were survival in ischemie area. The mRNA of TIMP-3 in ischemic myocardium was significantly higher in group A than group s B and C （P 〈 0.01）, the mRNA of MMP-9 in ischemic myocardium was significantly lower in group A than in group s B and C （P 〈 0.01 ）. Conclusions Implanted TIM P-3 gene transfected VSMCs in ischemc myocardium can conspicuously reduce the expression of MMP- 9 and myocardium remodeling after AMI and improve the heart function.