骨髓间充质干细胞移植对急性心肌梗死大鼠心功能的改善作用

Ameliorative Effect of Rat Bone Marrow Mesenchymal Stem Cell Transplantation on Infracted Heart Function

本研究探讨大鼠骨髓间充质干细胞(rMSC)移植对急性心肌梗死大鼠心功能的影响及其作用机制。体外培养rMSC并采用流式细胞术检测细胞免疫表型。开胸直视下结扎大鼠冠状动脉左前降支,制作急性心肌梗死模型。实验动物分为3组:假手术组(只开胸腔不结扎冠状动脉前降支)、AMI组(开胸结扎后注射无血清DF12培养液)及rMSC组(开胸结扎后注入Dil标记的rMSC)。将rMSC移植至大鼠心肌梗死周边心肌组织内8周后,通过超声心动检查、生理多导仪检测各实验组大鼠左室射血分数(LVEF)、左室收缩末压(LVESP)、左室舒张末压(LVEDP)、左室压力最大上升或下降速率(+dp/dtmax,-dp/dtmax)等心功能指标;用免疫荧光共聚焦检测移植细胞的分化;免疫组织化学染色检测CD31抗原以了解梗死边缘区新生血管数量。结果显示:体外培养的rMSC表达CD90、CD44、CD105、CD54,不表达CD34、CD45、CD31。移植的rMSC在大鼠心肌组织内可分化为心肌样细胞;rMSC移植组大鼠梗死周边组织新生血管数量较对照组明显增多;移植组大鼠LVEF、LVESP、+dp/dtmax、-dp/dtmax较对照组均明显升高,而LVEDP明显下降。结论:rMSC移植后在心肌组织中可分化为心肌样细胞,可能促进新生血管形成,改善心肌梗死动物的心功能。

This study was purposed to investigate the effects of rat marrow mesenchymal stem cell （rMSC） transplantation on left ventricular（LV） function in a rat myocardial infarction model. Myocardial infarction was performed in male Lewis rats by ligating the proximal left coronary artery. Rats were randomly divided into 3 groups ： sham operation group（ only thoracotomy, n = 8 ）, AMI group （ DF12 injection, n = 10 ）, rMSC group （ Dil-Labeled rMSC transplantation）. At 8 weeks later, the cardiac functions including left venticular ejection fraction（ LVEF）, left venticular end systolic pressure（ LVESP）, left venticular end diastolic pressure（ LVEDP）, ＋ dp/dtmax and -dp/dtmax were evaluated by echocardiography and cardiac catheterization . The presence and differentiation of engrafted cells were assessed. CD31 was detected by immunohistochemical staining to demonstrate neovascular formation. The results indicated that the cultured in vitro rMSC expressed CD90, CD44, CD105, CD54; did not express CD34, CD45 ,CD31, as compared with AMI group, rMSC group showed a significant increase of LVEF, LVESP, ＋ dp/dtmax , -dp/dtmax and a significant decrease of LVEDP. Immunofluorescence demonstrated that some transplanted rMSCs were positive for myosin, suggesting that small number of transplanted rMSCs differentiated into cardiac-like cells, lmmunostaining showed marked augmentation of capillary density in the rMSC group than that of AMI group. It is concluded that transplanted rMSCs can differentiate into cardiac-like cells and rMSC transplantation can improve LV function after myocardial infarction in rats.