TIMP-3基因转染的血管平滑肌细胞移植对心肌梗死后心脏形态和功能的影响

贾智博; 田海; 苗宏志; 刘开宇; 孙露; 蒋树林; 李仁科

TIMP-3基因转染的血管平滑肌细胞移植对心肌梗死后心脏形态和功能的影响

Effects of transplantation of tissue inhibitor-3 of matrix metalloproteinase gene-transfected vascular smooth muscle cells on heart structure and function after myocardial infarction

摘要

摘要: 目的: 观察基质金属蛋白酶组织抑制因子3 (tissue inhibitor-3 of matrix metalloproteinases，TIMP-3)基因转染的血管平滑肌细胞(vascular smooth muscle cells，VSMCs)移植，对大鼠心肌梗死后心脏形态和功能的影响。方法: 取Wistar大鼠胸主动脉采用组织块贴壁法培养VSMCs。应用脂质体转染技术，将TIMP-3-pcDNA3.0重组质粒瞬时转染至VSMCs。另取雌性Wistar大鼠121只（体质量200～250 g），其中93只建立急性心肌梗死模型。将存活的84只随机分成A、B、C 3组（每组28只），即于心肌梗死后3 d，再次开胸并在梗死的心肌中分别注射含有3×106个TIMP-3基因转染的VSMCs（A组）、3×106个VSMCs（B组）或改良Eagle培养基（Dulbeccos modification of Eagles medium Dulbecco，DMEM培养基）（C组）各0.3 ml，121只中剩余的28只大鼠作为正常对照组（D组），不做任何处置。基因转移4周后，进行超声心动图检测心脏的功能，然后获取心脏标本，计算心脏左室容积(left ventricular volume，LVV)和左室容积指数(left ventricular volume index，LVVI)，最后进行心脏组织学观察。结果: 成功分离、培养了VSMCs，纯度达98%，TIMP-3基因成功转入VSMCs中。基因转移4周，超声心动图检查发现，心脏功能的各项指标A组优于B组和C组，B组优于C组；但A、B、C 3组均差于D组（P均<0.05）。A、B、C和D组心脏LVV分别为(894.4±158.3)mm3、(1 126.5±284.7)mm3、(1 372.8±181.9)mm3和(420.2±39.6)mm3，LVVI分别为(2.957±0.362)mm3/g、(3.604±0.710)mm3/g、(4.538±0.259)mm3/g和(1.009±0.134)mm3/g，A、B、C 3组均明显大于D组，A、B组较C组明显减小，A组较B组明显减小（P均<0.05）。组织学观察显示，C组呈心肌梗死表现，B组梗死心肌内可见成簇的肌细胞，室壁较C组增厚；A组较B、C组梗死区缩小、室壁增厚，D组无异常。结论: 大鼠心肌梗死后3 d，将TIMP-3基因转染的VSMCs移植入梗死心肌内，可明显改善心脏的形态及功能。

Abstract: AIM: To investigate the effects of transplantation of tissue inhibitor-3 of matrix metalloproteinase (TIMP-3) gene-transfected vascular smooth muscle cells (VSMCs) on heart structure and function after myocardial infarction (MI) in rats. METHODS: VSMCs were obtained from rat thoracic aorta by tissue-piece inoculation. TIMP-3 gene was transfected into VSMCs by lipidosome-mediated method. One hundred and twenty-one female Wistar rats, aged 12 weeks and weighing between 200 and 250 g, were prepared. Acute MI models were established in 93 rats by ligating the descending left coronary artery; 84 survived and were divided randomly into three groups (n=28). Three days after MI, rat chests were opened again and 0.3 ml Dulbecco’s modified Eagle’s medium (DMEM) containing 3×106 TIMP-3 gene-transfected VSMCs (group A), 3×106 VSMCs (group B) or 0.3 ml DMEM (group C) was immediately injected into the infarcted myocardium. The control group (group D) consisted of 28 rats without any treatment. Heart function was detected by ultrasonic echocardiogram. Heart samples were harvested and heart left ventricular volume and volume index were measured. Heart structure was also observed by tissue morphologic examination. RESULTS: VSMCs were cultivated and had a high purity (98%). TIMP-3 gene was transfected into VSMCs successfully. Four weeks after gene transfer, heart function in group A was improved over group B and group C (P<0.05), group B was improved over group C (P<0.05), but they were all poorer than group D (P<0.05. Left ventricular volume was (94.4±158.3) mm3, (1 126.5±284.7) mm3, (1 372.8±181.9) mm3 and (420.2±39.6) mm3 in the four groups, and volume index was (2.957±0.362) mm3/g, (3.604±0.710) mm3/g, (4.538±0.259) mm3/g and (1.009±0.134) mm3/g. The results of histological observation showed MI in group C. Clustering muscle cells were seen in infarction field in group B and heart ventricle wall was thicker than in group C. Infarction field in group A was smaller than in groups B and C. Heart ventricle wall in group A was thicker than in groups B and C. CONCLUSION: Implanted TIMP-3 gene transfected VSMCs in infarcted myocardium at 3 days after acute MI noticeably improves heart structure and function in rats.

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