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目的观察心肌梗死后移植内皮祖细胞(EPCs)时的细胞自噬变化,探讨自噬维持移植细胞存活和纤维蛋白凝胶保护细胞的作用。方法通过结扎左冠状动脉的前降支建立大鼠心肌梗死模型后,在正常区、梗死边缘区和梗死区分别注射从人脐带血中分选的EPCs。2 h后取注射处组织,作半薄切片,观察纤维蛋白凝胶承载的EPCs分布。定位后作超薄切片,透射电镜下观察EPCs的自噬结构变化以及纤维蛋白凝胶与EPCs和心肌的相容性。结果与正常区相比,梗死边缘区发生自噬的EPCs增多,细胞内自噬结构也增多。梗死区的移植细胞的自噬显著增强,有的细胞坏死或凋亡。纤维蛋白凝胶与移植细胞和心肌的相容性良好,移植的EPCs在纤维蛋白凝胶中充分伸展,有的EPCs与心肌细胞黏附。结论在梗死边缘区移植EPCs后,轻度缺血刺激细胞发生自噬,这有利于维持移植细胞存活。纤维蛋白凝胶承载EPCs可避免细胞丢失和促进存活。
Objective To observe the changes of autophagy after transplanted endothelial progenitor cells (EPCs) after myocardial infarction and to investigate the role of autophagy in maintaining the survival of transplanted cells and fibrin gel protecting cells. Methods The model of myocardial infarction was established by ligation of the anterior descending artery of the left coronary artery. EPCs isolated from human umbilical cord blood were respectively injected into the normal, infarct and infarct regions. After 2 h, the tissue of the injection site was taken for semi-thin section and the distribution of EPCs on fibrin gel was observed. After positioning for ultrathin sections, the changes of autophagy structure of EPCs and the compatibility of fibrin gel with EPCs and myocardium were observed under transmission electron microscope. Results Compared with the normal area, there were more autophagy EPCs and more autophagy in the marginal zone of infarction. Autophagy in the transplanted cells in infarcted area was significantly increased, and some cells were necrosis or apoptosis. Fibrin gel and transplantation cells and myocardial compatibility well, transplanted EPCs fully extended in the fibrin gel, and some EPCs and myocardial cell adhesion. Conclusions Autologous macrophages are stimulated by mild ischemia after transplantation of EPCs in the marginal zone of infarction, which is beneficial to maintain the survival of transplanted cells. Fibrin gel-loaded EPCs can prevent cell loss and promote survival.