糖尿病心肌缺血大鼠骨髓干细胞动员及心肌组织细胞因子的表达

Bone marrow stem cell mobilization and cytokines expression in ischemic myocardium in diabetic rats with myocardial ischemia

目的探讨糖尿病心肌缺血大鼠外周血骨髓干细胞动员和归巢的变化以及缺血心肌组织中血管内皮生长因子和肿瘤坏死因子α的表达变化。方法首先采用链脲佐菌素腹腔注射建立雄性SD大鼠糖尿病模型,然后通过开胸结扎冠状动脉左前降支建立糖尿病心肌缺血模型,并分为缺血1d组、缺血3d组、缺血7d组、缺血28d组;另设相应时间点的糖尿病对照组(开胸但不进行动脉结扎)和正常对照组(不进行腹腔注射和动脉结扎),每组6只。应用流式细胞术测定各组大鼠的外周血单个核细胞中CD34+细胞百分率;应用免疫组化法观察各组动物缺血心肌中CD34+细胞归巢以及血管内皮生长因子和肿瘤坏死因子α的表达。结果大鼠糖尿病心肌缺血组于术后出现骨髓干细胞动员,1周内达高峰,随时间延长减弱;同时术后1周内缺血心肌组织中相应地出现骨髓干细胞归巢以及血管内皮生长因子和肿瘤坏死因子α表达明显增加。结论糖尿病缺血心肌早期可通过组织局部血管内皮生长因子和肿瘤坏死因子α表达升高而动员骨髓干细胞进入外周血,并归巢至缺血心肌,从而启动自体保护机制。

Objective To investigate the bone marrow stem cell mobilization and homing changes of peripheral blood due to diabetic myocardial ischemia in rats and the change of expression of the vascular endothelial growth factor （VEGF） and the tumor necrosis factor α （TNFα） in ischemic myocardial tissue. Methods The diabetic model of male Sprague-Dawley rats was created by intraperitoneal injection of streptozotocin first. Then the diabetic myocardial ischemia model was established through ligation of the left anterior descending coronary artery. The rats were divided into ischemic day-l, day-3, day-7, and day-28 groups. And their time-matching diabetic sham operation control group and normal sham operation control group were also established, with 6 rats in each group. Flow cytometry was used to measure the percentage of CD34＋ cells in peripheral blood mononuclear cells for each group. Immunohistochemistry was used to observe the homing of CD34＋ cells and the expression of VEGF and TNFα in the ischemic myocardium. Results The mobilization of bone marrow stem cells was initiated after the surgery in the rat models of myocardial ischcmia in diabetes and it peaked within 1 week and decreased with the passage of time. Accordingly the homing of CD34＋ cells and the expressions of VEGF and TNFα in the ischemic myocardium were significantly increased. Conclusion During the early stage, the diabetic ischemic myocardium can mobilize bone marrow stem cells into the peripheral blood and start homing to the ischemic myocardium by increasing VEGF and TNFα in the ischemic myocardium, thereby initiating the self-protection mechanisms.