经冠脉移植骨髓单个核细胞和间充质干细胞治疗急性心肌梗死的对比实验研究

Comparison study of intracoronary autologous bone marrow mononuclear cells and mesenchymal stem cells used in treatment of acute myocardial infarction

目的对比研究经冠脉骨髓单个核细胞(BM-MNC)和间充质干细胞(MSC)移植对实验性急性心肌梗死(AMI)心功能的影响及其机制。方法选用12只雄性冀中白猪随机分为:正常对照组、AMI模型组、BM-MNC组、MSC组各3只,经导管球囊封闭前降支制作AMI的动物模型,于梗死后1 h直接冠脉球囊成型术后经OTW球囊注入骨髓干细胞。分别于术前及术后4 w经心脏超声检测心功能,4 w后取材行光、电镜病理学检查,实时定量RT-PCR检测心肌血管内皮生长因子(VEGF)和碱性成纤维细胞生长因子(bFGF)mRNA表达。结果4 w时干细胞组比AMI模型组室壁运动异常指数显著减轻(P<0.05)、射血分数显著提高(P<0.01)。与AMI模型组相比:BM-M;NC和MSC组梗死区及梗死边缘区血管数显著增多、BM-MNC组增加比MSC组显著(P<0.01),心肌细胞凋亡指数显著降低,BM-MNC组及MSC组间无明显差异(P<0.01)。干细胞移植组梗死边缘区冠脉血管周围可见异常细胞生长,有毛细血管“芽生”现象,可见不成熟的心肌细胞和细胞凋亡。4 w时左室射血分数(LVEF)与心肌血管数成正相关(r=0.694 9,P=0.037 7),LVEF与心肌细胞凋亡指数成负相关(r=0.913 3,P=0.000 6)。BM-MNC组,心肌梗死区及梗死边缘区VEGF基因表达比其他三组均明显增加(梗死区F=4.23,P=0.045 6,边缘区F=5.66,P=0.022 3)。BM-MNC及MSC组心肌梗死区bFGF基因表达比梗死模型组显著增加(梗死区F=7.49,P=0.010 4)。结论经冠脉骨髓单个核细胞和间充质干细胞移植均可改善实验性AMI心功能;改善心功能的机理与梗死区及梗死边缘区VEGF及bFGF表达增加,血管密度增加,心肌细胞凋亡减少有关;骨髓单个核细胞移植的促血管增生作用优于间充质干细胞移植。

Objective To study the effects and mechanism of intracoronary autologous bone marrow mononoclear cells （BM-MNC） and mesenchymal stem cells （MSC） on the cardiac function of acute myocardial infarction （AMI）. Methods Twelve male white swine were randomly divided into normal control group, AMI group, BM-MNC group and MSC group （n = 3 each group）. AMI models were made by transcatheter blocking left anterior descending. One hour later after AMI direct percutaneous coronary intervention was taken and bone marrow stem cells were infused into the criminal artery through over the wire （OTW） balloon. By the end of four weeks, cardiac function and light and electron microscope pathology were studied, at the mean time VEGF anti bFGF mRNA expression were detect hy quantification real-time RT-PCR. Results By the end of four weeks, wall motion index were significantly decreased （ P 〈 0. 05 ）, LVEF were significantly increased in stem cell transplant groups, the number of blood vessel were significantly increased （infarcted zone F = 65.50, P = 0. 000 1, marginal zone F =59. 67, P =0.000 1） and myocardial apoptotic index were significantly decreased （infarcted zone F = 16.61, P =0.000 8, marginal zone F = 17.89, P = 0. 000 7） on infarcted and marginal zone both in BM-MNC group and mesenchymal group than those in AMI group. Abnormal immature myocardial cells, apoptosis cells and blood capillary gemination were found in marginal zone by light and electron microscope. At four weeks LVEF had a positive correlation to myocardial capillary density（r =0. 694 9, P =0. 037 7） and had a negative correlation to myocardial apoptotic index （r = 0. 913 3, P = 0. 000 6）. The myocardial mRNA expressions of VEGF both in infarcted and marginal zone in BM-MNC group were significantly higher than those of the others （ infarcted zone F = 4. 23, P = 0. 045 6, marginal zone F =5.66, P =0. 022 3）. The bFGF expression in infarcted zone both in BM-MNC group anti MSC group were significantly higher than those in AMI group （ F = 7.49,P = 0. 010 4）. Conclusions Intracoronary transplant autologous BM-MNC and MSC can improve cardiac function in AMI swine. The increased myocardial VEGF and bFGF mRNA expression and capillary density and decreased myocardial apoptosis might play an important role in improving cardiac function. The effects of BM-MNC transpiantatiou on angiogenesis could be surpassed to those of MSC.