静脉移植骨髓间质干细胞改善大鼠梗死心脏功能

Improved Cardiac Function in the Infarcted Rats by Intravenous Transplantation of Bone Marrow Mesenchymal Stem Cells

目的:探讨经外周静脉途径移植骨髓间质干细胞治疗急性心肌梗死的有效性和可能的机制。方法:采用左前降支冠状动脉结扎术制备大鼠心肌梗死模型,24h后经尾静脉注入同种异体骨髓间质干细胞或磷酸缓冲液;分别于移植后3d和1个月取材,应用ELISA和免疫组化技术分析细胞移植对血管内皮生长因子(VEGF)表达的影响,通过免疫组化染色观察移植细胞的分化情况并计数血管;超声心动图连续检测大鼠心功能在术后各时间点的变化。结果:细胞移植术后3d,移植组VEGF蛋白的表达量明显高于对照组(P<0.01),免疫组化显示移植组心脏的梗死区及其周边区域的细胞内VEGF阳性着色明显强于对照组,1个月时明显减弱。移植术后1个月,在部分移植细胞中检测到心肌细胞或血管内皮细胞特异性蛋白的表达,血管计数显示移植组血管数量较同期对照组增加1.4倍(P<0.01);同时移植组心功能较对照组明显改善(P<0.01)。结论:通过促进梗死周边缺血心肌的血管新生和移植细胞分化,骨髓间质干细胞经外周静脉移植可作为急性心肌梗死治疗的另一条有效路径。

Objective: To investigate the efficacy and possible mechanisms of therapy of acute myocardial infarction (AMI) with peripheral intravenous delivery of bone marrow mesenchymal stem cells (MSCs). Methods: Primary MSCs collected from healthy male SD rats were cultured and expanded in vitro. AMI was induced by ligation of left anterior descending coronary artery. MSCs were delivered through each tail vein 24 hours after AMI, meanwhile the same volume of phosphate buffered solution were intravenously injected into the same quantity of infarcted rats, respectively. At day 3 and 1 month post-transplantation, the expressions of VEGF were determined by ELISA and immunohistochemistry. The differentiation of implanted cells and the number of vessels were examined by immunohistochemistry. The cardiac function was evaluated by echocardiography. Results: ELISA showed transplantation of MSCs (BMT group) significantly enhanced protein expression of VEGF than those of transplantation of phosphate buffered solution (PBS group) (P<0. 01) at day 3 post- transplantation, and then markedly reduced at 1 month. Immunohistochemistry revealed that expression of VEGF by transplantation of MSCs were promoted within cardiomyocytes in the infarction zone and the peri- infarct zone. At 1 month, the specific markers for myocardium or vascular endothelial cells were detected in a few transplanted bone marrow cells. The vessel count showed the number of blood vessels in BMTgroup was more than that of the control group at the same time (1. 4- fold, P<0. 01). The cardiac function in BMT group was improved significantly than that of the control group(P<0. 01). Conclusion: Intravenous transplantation of MSCs improved the infarcted cardiac function by upregulation of VEGF expressions in ischemic cardiomyocytes that enhanced angiogenesis and differentiation of MSCs. Peripheral intravenous delivery of MSCs may be an effective alternation for the treatment of AMI.