Abstract: Objective To explore the influence of neonate rats’ cardiomyocytes transplantation on myocardial capillary density and microvessel regeneration of rabbits with acute myocardial infarction(AMI). Methods Sixteen New Zealand white rabbits and 40 neonate rats were used in the study. After the model of AMI in rabbits was established, cultured neonate rats’ cardiomyocytes were injected into the area of AMI. Specimens were collected 1, 2, 3 and 4 weeks after transplantation, and they were stained by alkaline phosphatase(AlP) histochemical method and immunofluorescence method, then observed by light microscopy. The capillary density and regeneration around the marginal zone of AMI were assayed through LEICA Qwin V3 image analysis system. Results After neonate rats’ cardiomyocytes transplantation for 1, 2, 3 and 4 weeks, the capillary density and the number of regenerate capillary around the area of rabbit’s AMI were increased significantly than those of the control group. And through quantitative analysis, we found that myocardial capillary density tend to be increased first and then decreased.Conclusion Allogenic cardiomyocytes transplantation could promote neovascularization of acute infarcted myocardium of rabbits, and then improve the

Key words: Cardiomyocyte, Transplantation, Capillary density, Neovascularization, Enzyme histochemistry, Immunofluorescence, Rat, Rabbit