Experimental Study On Peripheral Blood Mononuclear Cells Transplantation And Bone Marrow Stem Cells Mobilization In Treatment Of Heart Failure After Myocardial Infarction

Objectives:To compare effects of peripheral blood mononuclear cells (PBMCs) transplantation and recombinant human granulocyte colony-stimulating factor (rhG-CSF) to mobilize bone marrow stem cells on heart function and vascular proliferation after acute myocardial infarction (AMI) in rabbits.Methods:Forty-five healthy rabbits aged five months were randomly divided into three groups (n=15). GroupⅠwas control group, groupⅡwas PBMCs transplantation group, and groupⅢwas rhG-CSF treated group. Myocardial infarction was induced by ligating left anterior descending coronary artery in all rabbits. In transplantation group (groupⅡ), PBMCs were isolated by density gradient centrifugation and nuclei were stained by Brdu. PBMCs transplantation was performed 30 minutes after AMI. In mobilization group (groupⅢ), rhG-CSF (30μg·kg-1·d-1) was injected subcutaneously after AMI and every 24 hours for 5 days. Control animals (groupⅠ) didn't receive any treatment after AMI. Left ventricular end-diastolic diameter (LVEDd) and left ventricular ejection fraction (LVEF) were measured by echocardiography before operation and at the end of the first and sixth week after operation. All rabbits were sacrificed after 6 weeks to get the heart to make pathological section. The size of infarcted myocardium was measured by HE stain. Monoclonal antibodies against Brdu were used to locate the implanted cells, and the counts of microvessel on the centre and margin of the infarcted myocardium were evaluated by immunohistochemistry.Results:1. In groupⅡ, PBMCs were successfully isolated from peripheral blood by density gradient centrifugation.2. LVEDd of groupⅠ, groupⅡ, groupⅢwere 12.98±1.38 mm, 12.72±1.04 mm, 12.94±1.37 mm and LVEF were 79.84±3.55%, 79.80±3.59%, 80.31±3.64% respectively before operation. There was no significant difference among them (P>0.05). At the end of the first week after operation, LVEDd of groupⅠ, groupⅡ, groupⅢwere 17.77±1.59 mm, 16.87±1.28 mm, 17.02±1.64 mm and LVEF were 50.98±6.78%, 52.14±5.61%, 53.72±4.91%. LVEF decreased significantly at the end of the first week after operation among these three groups (P<0.01). At the end of the sixth week after operation, LVEDd of groupⅠ, groupⅡ, groupⅢwere 17.71±1.64 mm, 16.03±0.94 mm, 15.97±1.52 mm and LVEF were 50.89±8.32%, 57.54±5.60%, 56.43±5.77% respectively. Compared with groupⅠ, LVEF were significantly improved in other two groups (P<0.05), but have no significant difference between groupⅡand groupⅢ(P>0.05).3. HE stain showed that the sizes of infarcted myocardium of groupⅠ, groupⅡand groupⅢwere 37.15±2.94%, 26.87±2.33%, 27.47±2.13% respectively. Compared with groupⅠ, the sizes of infarcted myocardium were significantly decreased in other two groups (P<0.01).4. Six weeks after transplantation, Brdu-stained cells were observed at the transplantation area in groupⅡ. The implanted cells mainly located in the local injection site and their shape different from the normal myocardial cells.5. The capillary density of groupⅠ, groupⅡ, and groupⅢassessed by immunohistochemical staining with monoclonal antibodies against factorⅧ-related antigen were 2.54±1.27, 8.40±1.96, 6.20±1.26 in the central area of infarction and 13.69±2.93, 25.33±3.75, 22.87±2.70 in the marginal area of infarction respectively. Compared with groupⅠ, the capillary density of infarcted myocardium were significantly increased in other two groups (P<0.01), especially in groupⅡ.Conclusions:1. The AMI model of rabbits can be successfully duplicated by ligating left anterior descending coronary artery.2. PBMCs transplantation and rhG-CSF mobilize bone marrow stem cells can promote vascular proliferation, decrease myocardial infarction size, inhibit ventricular remodeling after AMI and improve left ventricular function.