人脐血单个核细胞移植治疗大鼠急性心肌梗死的实验研究

Beneficial effects of human umbilical cord blood mononuclear cells transplantation on rats with experimental myocardial infarction

目的探讨人脐血单个核细胞(HUCBC)移植治疗急性心肌梗死(AMI)的可行性及疗效。方法雄性Wistar大鼠45只随机分为:心肌梗死(MI)对照组、MI+细胞移植组和正常组(每组各15只)。结扎冠状动脉左前降支制作大鼠AMI模型,以HES沉淀加Ficoll密度梯度离心的方法制备HUCBC,并以BrdU标记细胞。移植组大鼠模型制作成功后即刻在梗死区周边注射经分离并标记的HUCBC混悬液,在MI对照组相同位置注入等量DMEM培养液,正常组不做任何处理。移植4周后用超声评价心功能和左心导管检测血流动力学改变,并取心脏组织行HE染色、抗血管性血友病因子(vWF)和BrdU组化染色,观察心肌病理改变、毛细血管增生及移植细胞成活情况。结果在移植组显示移植的单个核细胞可在梗死心肌内存活并参与梗死心肌修复。超声心动图见移植组各项心功能指标改善。血流动力学检查显示移植组与MI对照组相比,左心室舒张末压明显降低[LNEDP (21．08±8．10)mm Hg(1 mm Hg=0．133 kPa)比(30．82±9．59)mm Hg,P<0．05],左心室内压力最大上升速率明显增快[+dp／dtmax(4．29±1．27)mm Hg／ms比(3．24±0．75)mm Hg／ms,P< 0．05],最大下降速率亦显著提高[-dp／dtmax(3．71±0．79)mm Hg／ms比(3．00±0．49)mm Hg／ms, P<0．05]。免疫组化染色发现移植组梗死区周边毛细血管数显著增加(P<0．01)。结论HUCBC在未使用免疫抑制剂的条件下可成功移植到大鼠MI区,并提示能改善MI大鼠心功能,促进新生血管形成。

Objective Human umbilical cord blood contains abundant immature stem/progenitor cells, which may contribute to the repair of infarcted myocardium. Present study aimed to explore the feasibility and effects of human umbilical cord blood mononuclear cells （HUCBC） transplantation for the treatment of myocardial infarction. Methods Forty-five male Wistar rats were randomly divided into three groups： （1） Myocardial infarction （MI plus vehicle, n = 15）, （2） MI plus cell transplantation （HUCBC were implanted into the peri-infarct area immediately after MI, n = 15）, （3） Normal control group （n = 15） . After echocardiography and hemedynamic measurements, the rats were sacrificed for histological and immunochemical examinations one month post MI. Results The transplanted HUCBC survived and participated the repair process in host heart. Significantly improved left ventricular function was evidenced by echocardiography in cell transplantation group compared to the MI control group. Left ventricular enddiastolic pressure was significantly reduced LVEDP （ 21.08 ± 8. 10） vs （ 30. 82 ± 9. 59） mm Hg, P 〈 0.05], ±dp/dtmax[（4.29±1.27） vs （3.24±0.75） mm Hg/ms, P〈0.05] and -dp/dtmaxincreased [ （3.71 ± 0. 79） vs （3.00 ± 0. 49 ）mm Hg/ms, P 〈 0. 05 ] in cell transplantation rats compared with MI control rats. vWF immunostaining examination showed significantly increased microvessles within the boundary of infarcted myocardium in cell transplantation group compared to the MI control group （ P 〈 0. 01）. Conclusions HUCBC transplantation may improve cardiac function in MI rats by promoting microvessel formation.