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背景:现已发现心肌梗死后心肌纤维化是心室重构的重要机制,而相关干细胞心肌移植对这一过程的影响报道不多。目的:观察自体骨骼肌卫星细胞移植对心肌梗死大鼠心肌纤维化的影响,并探讨其可能机制。设计、时间及地点:随机对照动物实验,于2007-07/09在解放军第三军医大学大坪医院野战外科研究所第三研究室完成。材料:Wistar大鼠45只,雌雄各半,体质量150～200g,其中30只用于制备心肌梗死模型。方法:45只大鼠按随机抽签法分为3组,每组15只。心肌梗死组:结扎冠状动脉左前降支造成心肌梗死,2周后沿梗死区与正常心肌交界处多点注射0.2mL无血清M199培养液;移植组:造模后将体外培养2周的大鼠自体卫星细胞0.2mL以注射的方式移植到大鼠梗死区周围。假手术组:不造模,仅在左前降支周围心前壁多点注射0.2mL生理盐水。主要观察指标:4周后测定各组大鼠缺血心肌血管内皮生长因子mRNA、血管内皮生长因子蛋白质的表达,缺血心肌毛细血管密度变化,苏木精-伊红染色观察各组心肌细胞在梗死区的生长、增殖情况。结果:①卫星细胞移植4周后,假手术组和心肌梗死组血管内皮生长因子mRNA和血管内皮生长因子蛋白表达较移植组明显降低(P<0.01);心肌梗死组大鼠毛细血管密度较假手术组升高(P<0.05);移植组大鼠缺血心肌中毛细血管密度较假手术组、心肌梗死组亦明显升高(P<0.01)。②苏木精-伊红染色显示假手术组大鼠心肌形态正常,结构清晰,心肌纤维排列整齐有序,肌纤维间无成纤维细胞聚集、增生现象。心肌梗死组大鼠心肌内可见成纤维细胞增生及胶原形成,心肌有序的基本结构发生紊乱。移植组大鼠其梗死区可见较多带有横纹且具有多核的肌细胞存在,组织排列较有序,纤维组织明显少于心肌梗死组。结论:卫星细胞在心肌梗死区中可增殖分化为具有弹性和收缩功能的横纹肌样细胞,并通过自分泌和旁分泌的形式分泌血管内皮生长因子促使缺血心肌毛细血管增生,从而有效地抑制了缺血心肌的纤维化进程。
BACKGROUND: It has been found that myocardial fibrosis after myocardial infarction is an important mechanism of ventricular remodeling. However, the effect of cardiac stem cell transplantation on this process has not been reported much. Objective: To observe the effect of autologous skeletal muscle satellite cell transplantation on myocardial fibrosis in rats with myocardial infarction and to explore its possible mechanism. DESIGN, TIME AND SETTING: The randomized controlled animal experiment was performed at the Third Laboratory, Institute of Field Surgery, Daping Hospital, Third Military Medical University of Chinese PLA, from July 2007 to 09. MATERIALS: Forty-five Wistar rats, male and female, weighing 150-200 g, of which 30 were used for the preparation of myocardial infarction model. Methods: Forty five rats were randomly divided into three groups (n = 15). Myocardial infarction group: ligation of the left anterior descending coronary artery caused by myocardial infarction, 2 weeks after the infarction and normal myocardium at the junction of multi-point injection of 0.2mL serum-free M199 culture; transplantation group: the model will be cultured in vitro 2 weeks after the rat autosatellite 0.2mL cells were injected into the infarct area around the rats. Sham operation group: no modeling, only in the left anterior descending artery around the anterior multifarious injection of 0.2mL saline. MAIN OUTCOME MEASURES: After 4 weeks, the expression of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor (VEGF) protein, the changes of capillary density in ischemic myocardium were determined, and the changes of myocardial cells Infarction area growth and proliferation. RESULTS: ① After 4 weeks of satellite cell transplantation, the expressions of VEGF and VEGF in sham operation group and myocardial infarction group were significantly lower than those in transplantation group (P <0.01). The capillary density in myocardial infarction group was significantly lower than that in the control group (P <0.05). The capillary density in the ischemic myocardium in the transplantation group was significantly higher than that in the sham operation group and the myocardial infarction group (P <0.01). ② Hematoxylin-eosin staining showed that the myocardium of sham operation group was normal, the structure was clear, the arrangement of myocardial fibers was orderly and orderly, and there was no fibroblast aggregation and hyperplasia among muscle fibers. Myocardial infarction group showed myocardial fibroblast proliferation and collagen formation, the basic order of myocardial disorder. In the transplantation group, more myoblasts with horizontal stripes and multi-nucleus were found in the infarct area. The arrangement of tissues was more orderly and the fibrous tissue was less than the myocardial infarction group. CONCLUSIONS: Satellite cells proliferate and differentiate into striated muscle-like cells with elastic and contractile function in the myocardial infarction area and promote the proliferation of ischemic myocardium by autocrine and paracrine secretion of vascular endothelial growth factor, thus effectively inhibiting Ischemic myocardial fibrosis.