经冠状动脉移植骨髓间质干细胞治疗心肌梗死的实验研究

Transcoronary Implantation of Bone Marrow Stromal Cells Improves Heart Function After Myocardial Infarction

目的:观察经冠状动脉输注骨髓间质干细胞移植的疗效。方法:成年犬21只,分为对照组(n=12)与移植组(n=9)。结扎冠状动脉左前降支后,移植组于冠状动脉内注入经标记的自体骨髓间质干细胞悬液,对照组仅注入培养基。6周后,对比病理、超声心动图及血流动力学指标的变化。结果:骨髓间质干细胞培养两周可增殖达5．0×107个细胞,移植前经4’,6-二脒基-2-苯吲哚(DAPI)染色后的标记阳性率近100％。移植6周后梗死区内可见DAPI标记阳性的细胞,其α肌动蛋白(α-actin)(+),并与周围的宿主细胞形成缝隙连接,Connexin43(+)。每个高倍视野(0．2 mm2)的瘢痕区毛细血管的数量,移植组显著高于对照组[(5．49±0．50)支比(2．03±0．46)支,P<0．01]。6周时移植组与对照组相比,左心室压力最大上升及下降速率(±dp／dtmax)及心输出量均显著上升[其数值分别为(3 057±1 246)mmHg／s比(1 569±618)mmHg／s,P<0．05;(3 107±1 031)mmHg／s比(1 465±647)mmHg／s,P<0．01;(1．88±0．28)L／min比(1．41±0．29)L／min,P<0．01],左心室射血分数显著提高(0．48±0．09比0．35±0．05,P<0．01)。实验中未发现明显的不良反应发生。结论:经冠状动脉输注骨髓间质干细胞移植,能够分化为心肌样细胞,促进梗死区新血管形成并改善心脏功能。

Objective： To test the therapeutic effectiveness of transcoronary implanted stromal cells using a canine model. Methods： The canine acute coronary occlusion model was created by ligating the left anterior descending artery （LAD）. After LAD ligation, bone-marrow derived stromal cells were injected into the ligated coronary artery. Results： Six weeks later, lots of 4＇ ,6-Diamidino-2-phenyindole （DAPI） labelled stromal cells were identified in the scar tissue, expressing myogenic-specific protein of α-actin. Some stromal cells were found to be connected to the adjacent host cardiomyocytes with gap junction （ connexin 43 staining positive）. Cardiac function was evaluated by echocardiography at 6 weeks after implantation. Left Ventricular Ejection Fraction （LVEF） was improved（0. 48±0. 09 vs 0. 35±0.05, P 〈 0. 01 ）. The hemodynamic parameters including ± dp/dtmax and cardiac output were increased in the cell therapy group （P 〈 0. 05 ）. Stromal cell transplantation induced angiogenesis in the scar, and the number of capillary vessels per high-power field （0. 2mm^2 ） in the cell therapy group was 5.49±0. 50 （ and 2.03 ±0.46 for control group, P 〈0. 01 ）. Conclusions： This study demonstrated for the first time that bone-marrow stromal cell delivered via coronary artery are capable of targeted migration, differentiation into cardiomyocytes in the scar tissue and improvement of heart function.