激活Notch信号的骨髓间充质干细胞心肌移植促血管新生的研究

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

目的:探讨干预Notch信号的骨髓间充质干细胞(BMSCs)移植对心肌梗死(MI)大鼠心肌中治疗性血管新生的作用及其机制。方法:60只Wistar大鼠通过结扎冠状动脉前降支(LAD)建立MI模型。建模后2周,进行相应处理后,随机分为激活Noth信号的BMSCs移植实验组(D组)、BMSCs移植对照组(E组)、培养液移植对照组(C组)及MI模型对照组(B组),每组15只大鼠。另选取10只大鼠为假手术对照组(A组)。4周后,观察细胞生长及增殖情况,运用ELISA法血浆中VEGF浓度,免疫组织化学法及Western blot法测定缺血心肌中血管内皮细胞生长因子(VEGF)蛋白的表达及缺血区心肌中毛细血管密度的改变。结果:BMSCs在梗死区中可增殖分化为内皮细胞,与B组、C组及A组相比,D组、E组缺血心肌中VEGF蛋白的表达增多及毛细血管密度均明显增加(P<0.01),D组较E组更明显(P<0.05)。结论:Notch信号可促进心肌梗死区BMSCs向内皮细胞分化,并通过自分泌和旁分泌的方式增加缺血心肌中VEGF的表达,从而促进缺血心肌中毛细血管新生。

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（P0.01）.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（P0.01）.Capillary density in the BMSCs with Notch signal activation transplantation group was higher than that in BMSCs transplantation group（P0.01）.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.