| OBJECTIVES: It is to study the effect to cardiac function by transplantation of autologous bone marrow mesenchymal stem cells at different times after myocardial infarction by which created the model of ischemic -myocardial infarction in swines by embolization in the distal end of the left anterior descending branch (LAD) with a gelatin sponge through cardiac catheter, and explore its mechanism initially.METHODS: 30 milliliter bone marrow was aspirated from the postero-superior iliac spine of Taihu Meishan swines. The mesenchymal stem cells(MSCs) were cultured.30 healthy Taihu Meishan swines were divided into three experimental groups(Each owned 5) to create the model of myocardial infarction. Each group transplanted autologous bone marrow mesenchymal stem cells(MSCs) through coronary artery in three hours, two weeks and four weeks after myocardial infarction, which was called transplanting group of acute stage, transplanting group of two weeks and transplanting group of four weeks in short. Each group created control group(5),and injected DMEM culture medium through coronary artery in each correspond period, which was called control group of acute stage, control group of two weeks and control group of four weeks in short, and observed the change of each index of cardiac function with MRI, Doppler to each swine before myocardial infarction, transplantation and experimental observative terminus, and detected VEGF numerus of blood serum in different period after cell's transplantation. It could acquire swine's hearts after eight weeks in the experimental observative terminus, detect the condition of field planting and differentiation in cardiac muscle by the method of immunity histochemistry , and detect the density of blood vessels in cardiac muscle.RESULTS: Transplanting group of acute stage and each control group after myocardial infarction didn't find the survival transplanted cells. Compared to control group, there was no statistic disparity in left ventricle function and the percentage of the cicatrix area. Compared to control group, each index of cardiac function was all ameliorated including EF,LVEDD,LVESD and so on in experimental groups of the transplanting groups of two weeks and that of four weeks after myocardial infarction. Each index of transplanting group of four weeks after myocardial infarction ameliorated better than that of transplanting group of two weeks after myocardial infarction(P<0.05). After myocardial infarction eight weeks, it was displayed by cardiac MRI that there was no statistics sense of the disparity on absolute value of reduction percentage in the area of myocardial infarction in proportion to that of left cardiac ventricle of transplanting group of acute stage and each of its control group. Compared to transplanting group of two weeks, the absolute value of reduction percentage in the area of myocardial infarction in proportion to that of left cardiac ventricle of transplanting group of four weeks was large , which disparity had statistic sense(P<0.05). The numerus of blood serum VEGF of transplanting group of two weeks and that of four weeks after myocardial infarction rose significantly after stem cell's transplantation, but there was no obvious change in the numerus of blood serum VEGF of transplanting group of acute stage and that of its control group. Compared to that of transplanting group of two weeks after myocardial infarction, the ascensus argument of blood serum VEGF of transplanting group of four weeks after myocardial infarction was high, which disparity had statistic sense(P<0.05).The immunity histochemistry of the cardiac muscle section of transplanting group of acute stage and each of its control group had no permanent planting and cell differentiation after myocardial infarction eight weeks. The immunity histochemistry result of the cardiac muscle section of transplanting group of two weeks and that of four weeks displayed that there was permanent planting and cell differentiation of the transplanting cells. Permanent planting and cell differentiation of transplanting group of four weeks was superior to that of two weeks, which disparity had statistic sense (P<0.05). The immunity histochemistry result displayed the blood vessel density of the cardiac muscle after myocardial infarction eight weeks. The disparity of the blood vessel density of the cardiac muscle by immunity histochemistry of transplanting group of acute stage and each of its control group had no statistic sense. The blood vessel density of the cardiac muscle by immunity histochemistry of transplanting group of four weeks was higher than that of two weeks, which disparity had statistic sense(P<0.05).Comparison of the blood vessel density of the cardiac muscle among each experimental group had significant differences. The blood vessel density of the cardiac muscle of experimental group after myocardial infarction four weeks was higher than that of three hours and that of two weeks(P<0.05).CONCLUSIONS:(1)There is disparity in the effect to cardiac function by transplantation of autologous bone marrow mesenchymal stem cells at different times after myocardial infarction.(2)Transplantation of bone marrow mesenchymal stem cells in acute stage of myocardial infarction has no significant effect to cardiac function, and transplantation of bone marrow mesenchymal stem cells in inacute stage can ameliorate cardiac function .The therapeutic effect of bone marrow mesenchymal stem cells transplantation after myocardial infarction four weeks is superior to that of two weeks. The therapeutic effect of bone marrow mesenchymal stem cells transplantation after myocardial infarction two weeks and that of four weeks are all superior to each of its control group.(3) The microenvironment of cardiac muscle in different period after myocardial infarction impacts on the permanent planting, survival and cell differentiation of bone marrow mesenchymal stem cells in the infarct cardiac muscle after being transplanted. |
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