Study of transplantation of activation of Notch signal of bone mesenchymal stem cells into myocardium to promote vasa sanguefera neogenesis

AIM:To study the effect and mechanism of transplantation of activation Notch signal of bone mesenchymal stem cells (BMSCs) into myocardium of myocardial infarction to promote vasa sanguefera neogenesis. METHODS: Sixty Wistar rats with ligation of anterior descending (LAD) coronary artery as a myocardial infarction (MI) model were randomly divided into BMSCs with Notch signal activation transplantation group, BMSCs transplantation control group, culture medium transplantation control group, and AMI model group. Cells, culture medium and 0.9% sodium chloride injection were injected into the scar tissue of transplantation (n=15), control (n=15) and sham-operated animals (n=10) respectively, 2 weeks later. Four weeks after injection, expression of VEGF protein and capillary density in the ischemic myocardium were determined by immunohistochemical method, and expression of VEGF mRNA in the ischemic myocardium was detected by reverse transcription polymerase chain reaction. The differentiated myofibers from BMSCs in the infarcted site were observed by pathological examination and immunohistochemical method. RESULTS: BMSCs progressively differentiated into striated muscle fibers at the myocardial infarction site. Compared with those in the MI and sham-operated control groups, expressions of VEGF mRNA and VEGF protein in the ischemic myocardium markedly increased in BMSCs with Notch signal activation transplantation group and BMSCs transplantation group (P<0.01). Compared with that in the control groups, capillary density in the ischemic myocardium markedly increased in BMSCs with Notch signal activation transplantation and BMSC transplantation group (P<0.01). Capillary density in the BMSCs with Notch signal activation transplantation group was higher than that in BMSCs transplantation group (P<0.01). CONCLUSION: BMSCs with Notch signal activation, after being implanted into the myocardial infarction site, show not only myocardial regeneration but also the ability to improve the expression of VEGF mRNA and VEGF protein in the ischemic myocardium and also increase vasa sanguefera neogenesis in the ischemic myocardium.