骨髓间质干细胞移植对心力衰竭大鼠心室重构影响的实验研究

Effects of bone marrow mesenchymal stem cells transplantation on heart function and ventricular remodeling in rats with isoproterenol-induced congestive heart failure

目的研究骨髓间质干细胞移植对异丙基肾上腺素致心力衰竭（心衰）大鼠心脏功能及心室重构的影响，进而探讨细胞移植影响心脏功能的可能机制。方法雄性Wistar大鼠60只，取其中的10只作为假手术组，单纯开胸。另外50只皮下注射异丙基肾上腺素（170mg／kg）连续4d，建立大鼠心衰模型。末次给药后4周，将左心室射血分数〈70％的大鼠（共26只）随机分成2组：移植组（n=13）和对照组（n=13），前者心肌内注射来源于雄性Wistar幼鼠的骨髓间质干细胞悬液（2×10^7／ml，150μl），后者心肌内注射等量的细胞培养液。移植前和移植后4周，多普勒超声心动仪测定大鼠心脏功能、HE及Masson’s染色评估心肌病理学改变、荧光显微镜观察移植细胞、RT-PCR和Westernblot检测各组心肌组织中Ⅰ、Ⅲ型胶原、基质金属蛋白酶（MMP）-2，9的表达。结果心衰大鼠心肌组织发生了弥漫性纤维化。移植组左心室射血分数及短轴缩短率明显高于对照组[（78．51±6．78）％比（65．40±12．33）％，（42．09±6．53）％比（32．38±10．22）％，P均〈0．05]，左心室收缩末径明显小于对照组[（2．91±0．54）mm比（3．83±0．69）mm，P〈0．05]。移植组心肌组织内可以观察到移植细胞的存在，心脏纤维化面积明显小于对照组（P〈0．05），心肌组织内I、Ⅲ型胶原，MMP-2、MMP-9的表达下调。结论骨髓间质干细胞移植通过影响心室重构相关因子进而改善发生了弥漫性纤维化的心衰大鼠的心脏功能。

Objective To explore the effects of transplanted BMSCs （bone marrow mesenchymal stem cells） on cardiac function and ventricular remodeling in rats with isoproterenol （ISO） induced heart failure. Methods Wistar rats （n = 50） received ISO （ 170 mg· kg^-1 · d^-1 for 4 days） injection. Four weeks later, rats with left ventricular ejection fraction （ LVEF 〈 70%, n = 26） were randomly assigned to receive intramyocardially BMSCs （2 × 10^7/ml, 150 μl） injection （n = 13 ） or equal volume culture medium （ n = 13 ）. Another 10 normal rats served as normal controls. Four weeks after transplantation, heart function was assessed again by echocardiography, left ventricular morphology was evaluated through H＆E and Masson＇s trichome staining. Transplanted ceils were observed by fluorescent microscope. RT-PCR and Western blot were performed to examine the myocardial expressions of type Ⅰ and type Ⅲ collagens, as well as MMP-2 and MMP-9. Results LVEF[（78.51 ±6.78）% vs. （65.40 ± 12.33）%land LVFS [ fractional shortening, （42. 09± 6. 53 ） % vs. （ 32. 38 ± 10. 22 ） %, all P 〈 0O. 05 ] were significantly increased and LVDs [ left ventricular systolic diameter, （2.91 ± 0.54 ）mm vs. （3.83± 0.69 ）mm, P 〈 0.05] was significant decreased in BMSCs treated rats compared with culture medium treated rats. Myocardial fibrosis was also significantly attenuated in BMSCs rats than that in culture medium treated rats. The myocardial expressions of type Ⅰ and type Ⅲ collagens, as well as MMP-2 and MMP-9 were significantly decreased in the BMSCs group compared with those in culture medium treated group. Conclusions BMSCs transplantation can significantly improve heart function and attenuate LV remodeling in rats with ISO-induced heart failure mediated by reducing myocardial fibrosis and downregulation of myocardial MMP-2 and MMP-9 expressions.