血红素氧合酶-1修饰的骨髓间充质干细胞心肌移植对梗死后心肌细胞凋亡及左心室功能的影响

Effect of mesenchymal stem cells transfected with human heme oxygenase-1 (HO-1) gene on myocardial apoptosis and angiogenesis

目的:探讨血红素氧合酶-1(HO-1)修饰的骨髓间充质干细胞(MSCs)对心肌梗死后心肌细胞凋亡及左心室功能的影响。方法:取大鼠骨髓,体外分离扩增培养MSCs,HO-1腺病毒转染。结扎左前降支1 h后,分别将HO-1-MSCs、MSCs多点注射到大鼠心脏梗死区周边,对照组注射等量PBS。移植后第4 d,Westernblotting检测梗死区周边HO-1蛋白、促凋亡蛋白Bax的表达;ELISA检测梗死区周边组织细胞因子血管内皮生长因子(VEGF)、b-成纤维生长因子(bFGF)的表达,第7 d超声心动图检测各组大鼠心功能变化。4周后,取梗死区周边心肌行Masson染色和免疫组化CD34因子染色。结果:Adv-HO-1转染MSCs后获稳定表达;HO-1蛋白在HO-1-MSCs组的表达明显高于MSCs组和对照组(P<0.01);促凋亡蛋白Bax的表达明显低于其它2组(P<0.01);细胞因子VEGF、bFGF的表达不同程度地高于其它2组(P<0.01)。HO-1-MSCs组左室收缩功能各项指标明显优于其它2组(P<0.01)。移植4周后,HO-1-MSCs组梗死区周边毛细血管密度明显高于MSCs组和对照组(P<0.01),HO-1-MSCs组心室壁变厚,心室腔明显缩小,胶原蛋白沉积减少。结论:HO-1修饰的MSCs分泌细胞因子协同HO-1蛋白抑制心肌细胞凋亡,促血管新生,抑制心室重构,改善心功能。

AIM： To investigate the effects of mesenchymal stem cells （MSCs）transfected with human heme oxygenase- 1 （HO- 1 ）gene on myocardial apoptosis and angiogenesis. METHODS： MSCs were acquired from the bone marrow of adult rats. The cells were isolated, purified, cultured, and transfected with Adv - HO - 1 in vitro before transplantation. At I h after left coronary artery ligation, Adv - HO - 1 - MSCs or MSCs were directly injected into the border of cardiac infarction in rats. Western blotting analysis was used to measure HO - 1, and Bax protein expression in the border of cardiac infarction. ELISA was used to measure the expressions of VEGF and bFGF in the border of cardiac infarction. At 4 weeks after transplantation, the heart functions in survival rats were examined by the Buxco system. The rats were killed, then the myocardial infarct size was measured with Masson＇ s trichrome, and the expression of CD34 in myocardial infarction area was detected by immunohistochemical method. RESULTS ： HO - 1 - MSCs exhibited increased HO - 1 expression. The expression of HO - 1, VEGF and bFGF in the border of cardiac infarction in the rats treated with HO - 1 - MSCs were higher than those in the rats treated with MSCs and PBS （P 〈 0. 01 ）. However, the expression of apoptotic protein Bax was significantly lower than that in the rats treated with MSCs and PBS（P 〈 0. 01 ）. The number of capillary vessels in the border of cardiac infarction in the rats treated with HO - 1 - MSCs was significantly higher than that in the rats treated with MSCs and PBS. The cardiac function in the rats treated with HO - 1 - MSCs was better than that in the rats treated with MSCs and PBS（P 〈 0.01 ）. CONCLUSION： The favorable effect on heart function appears to be a combined outcome of HO - 1 and paracrine factors released by MSCs.