目的 观察不同时间经静脉移植人脐血单个核细胞(HUCBC)对心肌梗死(MI)大鼠心功能及结构重构的影响.方法 入选雄性Wistar大鼠共80只, 结扎左前降支,制备心肌梗死模型,于梗塞后1 d、5 d、10 d以及30 d经尾静脉注入0.5 ml人脐血[含单个核细胞(1～3)×107]或0.5 ml 磷酸盐缓冲溶液(PBS).不使用免疫抑制剂.术后4周行超声心动图和血流动力学检查,随后处死大鼠,取出梗死心肌,以甲醛固定,进行苏木素伊红(HE)染色以及转移酶介导的三磷酸脱氧鸟苷-生物素刻痕末端标记(TUNEL)计算凋亡细胞.结果 PBS组大鼠左室明显扩大,梗死部位变薄.移植后瘢痕面积减少,室壁较对照组增厚.5 d和10 d移植瘢痕面积明显减小.与对照组相比,5 d和10 d移植大鼠左室射血分数(EF),左室压力最大变化率(±dp/dtmax)明显升高,左室收缩末内径(LVESD)明显减小,左室后壁(LVPW)增厚率更高.而梗死后10 d移植EF,±dp/dtmax ,以及LVPW增厚率的改善最明显.移植大鼠心肌和对照组相比凋亡细胞没有明显差异.结论 大鼠心肌梗死后5 d和10 d经静脉移植HUCBC可以明显抑制心室重构,改善心功能.在梗死后第10天移植对梗死心肌的结构重塑改善最明显,但对细胞凋亡没有明显作用.%Objective To study the effects of intravenous transplantation of human umbilical cord blood mononuclear cells( HUCBC )in the different time on heart functions and ventricular remodeling in rats with mvocardial infarction. Methods Myocardial infarrtion was established by ligation of the left anterior descending coronary aitery ( LAD )in rats. Equal volume injection of HUCBC or PBS( phosphate buffered saline )were injected through caudal vein at 1 day, 5 day, 1O day and 30 day after MI, respectively( n = 10 in each group ). 4 weeks after HUCBC implantation , echocardiography and hemodynamic evaluations were determined. Myocardial apoptosis was examined by TUNEL method. Results The scar size reduced in transplantation rats. Left ventrirular EF and + dp/dtmax were significantly increased, and left ventricular dimensions ( LVESD and LVEDD ) were significantly smaller in 5 day and 1O day transplantation rats than that in control rats. The amount of the myocardial apoptosis has not significant difference hetween transplantation and control group. Compared with in the other transplantation groups, EF,LVPW thickening and + dp/dtmax improved significantly in 10 - day transplantation groups. Conclusion Intravenously administered HUCBCs could improve the ventricular remodeling and cardiac function when transplanting at 5 day and 10 day after MI. The hest henefit was achieved in 10 days.
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