MRI study of transplanting autologous bone marrow mesenchymal stem cells at different time points on cardiac function amelioration following myocardial infarction / 中国组织工程研究

ABSTRACT

OBJECTIVE: To study the effect of transplanting autologous bone marrow mesenchymal stem cells (BMSCs) at different time point after myocardial infarction on cardiac function, and to approach its mechanism. METHODS: Thirty healthy Taihu Meishan swine were prepared for myocardial infarction models, and divided into 6 experimental groups, with 5 animals in each group. BMSCs were transplanted into 3 groups through coronary artery at 3 hours, 2 weeks and 4 weeks after myocardial infarction, named G1, G2 and G4, respectively. Meantime, DMEM culture medium was injected in the control group at correspond periods. Each swine was examined by MRI and Doppler before infarction, before transplantation, and at 8 weeks after infarction, respectively, to observe the change of cardiac function. The VEGF values of blood serum in different periods after transplantation were detected. All swine hearts were harvested after 8 weeks (the experimental terminus), and the planting and differentiation of transplanted cells in cardiac muscle were detected by the method of immunity histochemistry. The density of blood vessels in cardiac muscle was acquired simultaneously. RESULTS: There was no statistic difference of cardiac function between G1 and its control groups. The groups of G2 and G4 could improve cardiac function compared to the control groups, and G4 was superior to G2 (P < 0.05). There was no statistics difference of the decreased absolute value of myocardial infarcted area between G1 and the control groups. The myocardial infarcted area of G4 was greater than G2 (P < 0.05). The value of blood serum VEGF rose obviously in the G2 and G4, while G1 and all control groups did not present any marked changes, the rising amplitude of G4 was larger than G2 (P < 0.05). There were not any planting and differentiation of transplanted stem cells in G1 and all control groups at 8 weeks after infarction, but G2 and G4 could display, especially in G4 group (P < 0.05). There was no statistic difference of the density of blood vessels in cardiac muscle between G1 and all control groups at 8 weeks after infarction, but the differences were significant in all experimental groups, which was superior in G4 group to G1 and G2 groups (P < 0.05).CONCLUSION: There is disparity of transplanting BMSCs at different time point after myocardial infarction on cardiac function. Transplantation in acute period of myocardial infarction has no significant effect, but transplantation in non-acute period can ameliorate cardiac function. The therapeutic effect of transplanted at 4 weeks is superior to other time point. The MRI can display the location and compass of infarct cardiac muscle, and reflect the variation of cardiac function.