同种异体骨髓单个核细胞移植对急性心肌梗死后大鼠心肌细胞凋亡及相关基因表达的影响

目的:探讨大鼠同种异体骨髓单个核细胞(bone marrow mononuclear cells,BM-MNCs)急性心肌梗死区内移植对大鼠心肌细胞凋亡及相关基因表达的影响.方法:健康雄性Wistar大鼠24只,用结扎冠状动脉左前降支的方法建立大鼠心肌梗死模型后,分别将制备的培养基(对照组)和BM-MNCs悬液(移植组)由心外膜下植入梗死心肌周围.移植术后4周,超声心动图评价左室形态及功能,采用TUNEL法检测心肌细胞凋亡,免疫组化法检测心肌细胞中Bcl-2、Fas、FasL蛋白的表达水平,同时观察梗死区心肌内移植BM-MNCs及其周边区组织形态学特点.结果:移植术后4周,移植组左室收缩末期内径和左室舒张末期内径明显低于对照组(P＜0.01),左室射血分数、左室短轴缩短率明显高于对照组(P＜0.01).TUNEL结果显示:移植组心肌细胞凋亡指数(AI)明显低于对照组(P＜0.05).免疫组化结果显示:与对照组相比,移植组心肌细胞中Bcl-2蛋白平均光密度值显著升高(P＜0.05),Fas、FasL蛋白平均光密度值显著降低(P＜0.05),同时观察到移植组心肌梗死区内有BrdU标记阳性的BM-MNCs移植细胞存活.结论:同种异体BM-MNCs移植可以抑制心肌梗死后心肌细胞凋亡的发生,改善急性心肌梗死后的心脏功能,其机制可能与其调节Bcl-2、Fas、FasL的表达有关.

Effects of allograft bone marrow mononuclear cell implantation on rat cardiac myocyte apoptosis and expression of apoptosis-associated genes after acute myocardial infarction

Aim: To investigate the effects of implanting allograft bone marrow mononuclear cells(BM-MNCs)in the area of acute myocardial infarction on rat cardiac myocyte apoptosis and expression of apoptosis-associated genes.Methods:Twenty four male healthy Wistar rats were divided into two groups at random:control group(AMI medium,n=12)and transplantation group(AMI BM-MNCs,n=12).As soon as the descending anterior branch of left coronary artery was ligated, the medium alone was injected into the peri-infarct area of control group and the medium with BM-MNCs labeled with BrdU were injected into the peri-infarct area of transplantation group. Four weeks later,the changes of left ventricular morphology and cardiac function were evaluated by echocardiography. Apoptotic cells and the expression of Bcl-2, Fas and FasL were detected using TUNEL and immunohistochemistry, respectively. Histomorphologic characteristics of BM-MNCs implanted in peri-infarct areas were observed. Results: Four weeks later, the left ventricular end-systolic diameter(LVEDs) and left ventricular end-diastolic diameter(LVEDd)in transplantation group were lower than those in control group ( P< 0.01)and the left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS) were higher than those in control group (P<0.01). Compared with the control group, the myocyte apoptotic index(AI) and the expression of Fas and FasL decreased significantly(P<0.05) and the expression of Bcl-2 increased significantly in the transplantation group (P<0.05). The BM-MNCs labeled with BrdU had been observed around the injected region through immunohistochemical examination. Conclusion: Allograft BM-MNCs can inhibit cardiomyocyte apoptosis by regulating the expression of Bcl-2,Fas and FasL and improve ventricular remodeling and cardiac function.