Y Chromosome Labeled Allogeneic Bone Marrow-derived Mesenchymal Stem Cells Transplantation Into Infarcted Rat Myocardium

Objectives: To detect the survival of Y chromosome labeled allogeneic bone marrow-derived mesenchymal stem cells(BM-MSCs) and observe the effects of exogenous hepatocyte growth factor(HGF) on the survival of MSCs in rat ischemic myocardium;To investigate the effects of BM-MSCs transplantation, HGF and combination therapy with MSCs and HGF on the function of heart with acute myocardial infarction. To determine the feasibility and the effects of allogeneic BM-MSCs transplantation and combination therapy with BM-MSCs and exogenous HGF to treat acute myocardial infarction.Methods: (1)The detection of the survival of Y chromosome labeled BM-MSCs in infracted rat myocardium. Mononuclear cells were isolated from the bone marrow of male Wistar rats by density gradient centrifugation with Percoll and cultured with L-DMEM in vitro. Sry of male Wistar rat was cloned and labeled with DIG. An acute myocardial infarction model was created by the ligation of left anterior descending artery in female Wistar rats. The 10 rats were then randomly divided into 2 groups: MSCs group and MSCs plus HGF group. They received intramyocardiac injection of allogeneic BM-MSCs in the center and border zones of infarcted myocardium. 8 weeks later, hybridization in situ was performed and computer image analysis was used for quantitative analysis of positive cells. (2)The combination therapy with allogeneic BM-MSCs and exogenous HGF to treat acute myocardial infarction of rats. 51 female Wistar rats were randomly divided into 4 groups: DMEM control group, MSCs group, HGF group and MSCs plus HGF group. After ligated anterior descending coronary artery, they received corresponding therapy. 8 weeks later, hemodynamics and left ventricular function were measured by catheterization;morphological parameters were measured and infarction area(IA), left ventricular sphericity index(SI) and dilatation index(DI) were calculated;interstitial type I and type III collagen volume fraction (CVF) in the infracted and noninfarcted zone (IZ, NIZ) wereanalyzed using polarizing microscope by picrosirius red staining;capillary density were detected by immunohistochemistry.Results: (1) BM-MSCs proliferated quickly with a population doubling time of 45.5 h. After a series of passages, the attached cells became morphological homogeneous. Cloned sry gene was specific to male rat. Sry positive cells were detected in both MSCs group and MSCs plus HGF group. But there were no significant difference in integral optical density(IOD) of sry positive cells between two groups. (2)There were no significant difference in mortality, IA, heart rate(HR), blood pressure(BP), left ventricular systolic pressure (LVSP), +dp/dtmax/LVSP, left and right ventricular actual weight (LVAW, RVAW), SI and DI between the four groups;Compared with control group, left ventricular end diastolic pressure (LVEDP), left ventricular relative weight (LVRW), the CVF of type I and type III in IZ of LV were all significantly decreased, in contrast to ±dp/dtmax and capillary density were all significantly increased in the three treatment group. There were no significant difference between MSCs group and HGF group except for -dp/dtmax/LVSP, interventricular septal thickness (IVST) and capillary density. There were no significant difference except for LVRW, RVRW, IVST and capillary density between MSCs plus HGF group and MSCs group or HGF group.Conclusions: Implanted allogeneic BM-MSCs survived in ischemic myocardium. HGF did not have a measurable effect on the survival of MSCs. The therapy of MSCs, HGF and MSCs plus HGF could induce angiogenesis and decrease collagen deposition, then profoundly improve left ventricular function. But the combination therapy with MSCs and HGF did not surpass the monotherapy of MSCs or HGF in the improvement of left ventricular function.