兔冬眠心肌模型骨髓干细胞动员及心肌组织中肿瘤坏死因子基因表达

Bone marrow stem cell mobilization to the peripheral blood and tumor necrosis factor-α expression in ischemic myocardium in rabbit models of hibernating myocardium

目的探讨兔冬眠心肌模型外周血骨髓干细胞的变化及缺血心肌组织中肿瘤坏死因子基因表达的变化。方法选用雄性日本大白兔为研究对象,通过开胸不全结扎冠状动脉左前降支方法建立冬眠心肌动物模型。将成功制备的24只兔模型随机分为4组,即缺血3d组、缺血7d组、缺血28d组和假手术对照组。应用流式细胞术测定各组模型动物外周血单个核细胞中CD34+细胞百分率,应用实时荧光定量PCR方法测定各组动物模型缺血心肌组织中肿瘤坏死因子mRNA表达。结果兔冬眠心肌模型于手术后出现骨髓干细胞动员,1周内达高峰,随时间延长逐渐减弱;同时相应地出现手术后1周内缺血心肌组织中肿瘤坏死因子mRNA表达明显升高,随时间延长表达逐渐降低。结论冬眠心肌可通过组织局部肿瘤坏死因子表达增高而动员骨髓干细胞进入外周血。

Objective To investigate the changes in peripheral blood bone marrow stem cells and tumor necrosis factor-α gene expression in the ischemic myocardium in rabbit models of hibernating myocardium. Methods Twenty-four male Japanese white rabbits were randomized into 4 groups, including a sham-operated group and 3 model groups with hibernating myocardium induced by partial ligation of the left anterior descending coronary artery. The percentage of CD34-positive cells in the peripheral blood was evaluated by flow cytometry, and TNF-α mRNA expression in the ischemic myocardium was determined by real-time RT-PCR in the 3 model groups （at 3, 7, or 28 days after the operation） and in the sham-operated group. Results In rabbits with partial ligation of the left anterior descending coronary artery, the percentage of CD34-positive cells in the peripheral blood and myocardial TNF-α mRNA expression were significantly increased at 3 and 7 days after the operation in comparison with those in the sham-operated group and those at 28 days postoperatively （P〈0.01）. No significant differences were found in the percentage of CD34 positive cells or myocardial TNF-α mRNA expression between the sham-operated group and the rabbits 28 days after the coronary artery ligation （P〉0.05）. Conclusion Bone marrow stem cell can be mobilized into the peripheral blood in rabbit hibernating myocardium model possibly by increasing TNF-α gene expression in the ischemic mvocardium.