骨髓间充质干细胞移植对心肌梗死后炎性细胞因子表达的调节

Bone marrow mesenchymal stem cell transplantation regulates inflammatory cytokines expression after myocardial infarction

目的：近来研究表明，骨髓间充质干细胞具有独特的免疫调节特性，实验拟观察骨髓间充质干细胞移植对梗死心脏炎性细胞因子表达的影响，以进一步认识干细胞治疗心肌梗死的可能机制。方法：实验于2006—11／2007-08在中南大学湘雅二医院心内科实验室和实验动物中心完成。①实验材料：清洁级SD大鼠由中南大学湘雅二医院实验动物中心提供，实验过程中对动物处置符合动物伦理学标准。②实验方法：提取体质量120-150g SD大鼠骨髓间充质干细胞，以溴脱氧尿嘧啶核苷标记。取体质量180—200g雄性SD大鼠，结扎冠状动脉前降支建立心肌梗死模型，将模型随机分为3组：假手术组：仅穿线不接扎血管；PBS溶液注射组：模型制作成功即刻心外膜注射PBS液；干细胞移植组：模型制作成功即刻心外膜注射溴脱氧尿嘧啶核苷标记的骨髓间充质干细胞，每组8只。③实验评估：于术后1，28d行心脏超声检测，测量大鼠射血分数、左室短轴缩短率和左室舒张末期直径以评价心脏功能，并进行免疫组织化学和western blot检测，分析移植细胞存活和炎性细胞因子的表达情况。结果：24只建模成功大鼠均进入结果分析。①术后28d，心脏超声检测显示与注射PBS溶液相比，移植骨髓间充质干细胞可以延缓心室重构，改善心功能[射血分数：（30．76±3．39）％，（24．06±4．71）％，P〈0．05;左室短轴缩短率：（29．33±4．87）％，（23．05±3．94）％，P〈0．05;左室舒张末期直径：（6．45±0．47）mm，（7．81±0．31）mm，P〈0．05]。②免疫组织化学检测显示，心肌梗死后即刻心外膜移植的骨髓间充质干细胞可以在宿主体内存活。③与注射PBS溶液相比，骨髓间充质干细胞移植可以明显降低肿瘤坏死因子α、白细胞介素6表达（P〈0．05），同时增加白细胞介素10表达（P〈0．05）。western blot检测与免疫组织化学结果一致。结论：骨髓间充质干细胞移植可以延缓心肌梗死大鼠心室重构，同时下调大鼠梗死心脏促炎细胞因子肿瘤坏死因子α和白细胞介素6表达，上调抗炎细胞因子白细胞介素10表达。

AIM： Bone marrow mesenchymal stem cells （BMSCs） process special immunological property. This study investigated the effect of BMSCs on myocardial inflammatory cytokines expression in rats after myocardial infarction to further analyze the mechanism of stem cells for myocardial infarction. METHODS： Experiments were performed at the Cardiology Laboratory and Experimental Animal Center of Xiangya Second Hospital of Central South University from November 2006 to August 2007. ①Clean SD rats were provided by Experimental Animal Center of Xiangya Second Hospital of Central South University. Animal intervention met animal ethical standards. ②BMSCs were harvested from SD rats （120-150 g） and labeled with bromodexyuridine. Male rat （180-200 g） models of myocardial infarction were made by ligating anterior descending coronary. Rat models were randomly divided into three groups with 8 rats in each group. Rat models in a sham operation group only received threading. Rat models in a PBS injection group were treated with phosphate buffered solution （PBS） via epicardium injection after myocardial infarction models were succeeded. Rat models in a BMSC transplantation group were administrated with stem cells labeled with bromodexyuridine after myocardial infarction models were succeeded. ③ Echocardiography examination was performed 1 day and 28 days after surgery to measure ejection fraction, left ventricular fractional shortening and left ventricular end-diastole diameter to assess cardiac function. Immunohistochemistry and Western blot were performed to investigate the injected cells and the expression of inflammatory cytokines. RESULTS： Twenty-four SD rats were included in final analysis. ①Echocardiography showed that compared to injection of PBS, transplantation of BMSCs delayed ventricular remodeling and improved ventricular function 28 days after surgery [Ejection fraction： （30.76±3.39）%, （24.06±4.71） %, P 〈 0.05; Fractional shortening： （29.33±4.87） %, （23.05±3.94） %, P 〈 0.05; Left ventricular end-diastolic dimension （mm）： （6.45±0.47） mm, （7.81±0.31） mm, P 〈 0.05]. ②Immunohistochemistry demonstrated that transplanted cells were found living in the hearts of the host. ③Compared to injection of PBS, BMSCs reduced the expression of tumor necrosis factor （TNF）-α and interleukin （IL）-6 （P 〈 0.05）, and simultaneously increased the expression of IL-10 （P 〈 0.05）. Western blot showed the same results as immunohistochemistry. CONCLUSION： Transplantation of BMSCs down-regulated TNF-α and IL-6 expression and up-regulated IL-10 expression besides the prolongation of ventricular remodeling in myocardial infarction rats.