[Mechanism of the angiogenic effect of bone marrow stromal cells implantation on acute myocardial infarction].

Aim: To study the mechanism of the therapeutic angiogenesis effect of bone marrow stromal cells (BMSCs) implantation on rat acute myocardial infarction models.

Methods: The rat acute myocardial infarction models were made by coronary artery ligation and divided into 2 groups at random. In the experiment group, twice passaged BMSCs were labeled with BrdU and then implanted into the infarction region of the recipients in 4 weeks. The control group was the model rats received only DMEM injection. In control group, the hearts were harvested on the day 3, 7, 14, 28, 42 and 56. The infarction regions were examined to identify the angiogenesis and the expression of the VEGF and bFGF. In experiment group, the hearts were examined on the day 42 and 56 after AMI (the day 14 and 28 after cells implantation).

Results: Viable cells labeled with BrdU could be identified in host hearts. Histologic examination found most donor cells within the infarction region expressed fibroblastic and endothelial phenotype. The transplantation regions had a greater capillary density than the control regions did (14 +/- 4.7/HPF vs 6 +/- 2.4/HPF, P < 0.05). In the control group, the expression of VEGF and bFGF within the infarction regions peaked on day 7, and then decreased over time. In the experiment groups, the expression of bFGF and VEGF on the day 42 and 56 had a higher level than the control group did.

Conclusion: The expression of VEGF and bFGF is significantly increased after cells therapy during the late phase of AMI. It indicates that BMSCs implantation promoted the angiogenesis is mediated by its differentiation into endothelium and the increased release of VEGF and bFGF.