另一类型内皮祖细胞移植在损伤血管内膜修复中的作用

Effect of transplantaion of another type of endothelial progenitor cells on repair of injured vessels

目的:观察体外培养的兔外周血另一种内皮祖细胞(EOCs)自体移植修复内膜球囊损伤血管的效果。方法:实验动物随机分为EOCs移植组(n=8)和对照组(n=8)。密度梯度离心法分离兔外周血单核细胞(MNCs),在EGM-2培养基的诱导分化下获得EOCs。将第二次传代的EOCs重悬于100μL生理盐水中移植至兔颈总动脉内膜球囊损伤血管局部(移植组),仅注入100μL生理盐水者作为对照组。同时用CM-DiI标记EOCs移植,进行细胞示踪。术后4周,荧光显微镜下观察标记细胞的分布,并测量内膜损伤血管段再生内皮覆盖率(RA/TA)和新生内膜增生程度(IA/MA)。结果:术后4周,荧光显微镜下,在血管中膜、新生内膜层和内膜表面均可见荧光标记的细胞。伊文思蓝染色显示,EOCs移植组的再生内皮覆盖率(89.1%±6.3%)显著高于对照组(62.1%±7.5%,P<0.01);与对照组比较,EOCs移植组的新生内膜形成明显减少,两者的IA/MA比值分别为0.88±0.14和0.44±0.06(P<0.01)。结论:EOCs移植可显著加速内膜损伤血管的再内皮化,并减少新生内膜的形成。

Objective To investigate the contribution of transplantation of ex vivo expanded endothelial outgrowth cells （EOCs） from peripheral blood on repair of balloon injured vessels in rabbits. Methods Animals were divided into two groups （n= 8）： EOCs transplantation group and control group. The mononuclear cells （MNCs） were isolated from rabbit peripheral blood by density-gradient centrifugation and cultivated in EGM-2, yielding EOCs. A rabbit model of balloon catotid injury was used to evaluate the effects of EOCs transplantation on endothelial regeneration and inhibition of neointimal formation. Immediately after denudation, EOCs （the second passage） in 100 μL saline or 100 μL saline alone （control） were administered into the lumen of injured artery. Meanwhile the cells were labeled by CM-DiI for cells tracking. Four weeks after transplantation, rabbits were killed. The endothelial regeneration rate （RA/TA） and IA/MA ratio in fluorescence-labeled EOCs were detected. Results Four weeks after transplantation, fluorescence-labeled cells were found in the media, neointima and on the luminal surface of injured segments. Evans blue staining result demonstrated that RA/TA ratio in EOCs transplantation group （89. 1 %±6.3%） was much higher than that in control group （62. 1%±7.5%, P〈0.01）. Meanwhile, compared with control group, there was a significant decrease of neointimal formation in EOCs transplantation group. The IA/MA ratios were 0.88 ± 0.14 and 0.44 ± 0.06, respectively （P 〈 0.01 ）. Conclusion Transplantation of ex vivo expanded EOCs to balloon-injured arteries can accelerate reendothelialization significantly and reduce neointimal formation.