重编程骨髓间充质干细胞治疗缓慢型心律失常的研究

The research of reprogrammed mesenchymal stem cells in treatment of bradyarrhythmia

目的:利用Tbx18重组慢病毒转染骨髓间充质干细胞,移植到猪窦房结损毁模型的右室心外膜下心肌,探索治疗缓慢型心律失常的新方法。方法:10只健康未成年猪随机分为实验组和对照组,每组各5只,通过电刀烧灼窦房结建立窦房结毁损模型,实验组移植携带Tbx18基因的骨髓间充质干细胞,对照组移植等量携带绿色荧光蛋白(GFP)基因的骨髓间充质干细胞。观察两组猪的心率变化及对儿茶酚胺的反应性,免疫荧光法检测细胞移植部位心肌组织中Tbx18的表达。结果:窦房结毁损前,实验组与对照组猪心率无明显差异[(108.8±4.2)次/min对(106.6±6.8)次/min,P>0.05];窦房结毁损后,实验组与对照组猪心率无明显差异[(42.0±7.3)次/min对(43.4±5.1)次/min,P>0.05]。细胞移植后第2周实验组的心率明显高于对照组[(84.0±3.1)次/min对(53.6±2.5)次/min,P<0.05];细胞移植后第3周起实验组心率开始出现下降趋势,但仍明显高于对照组(P均<0.05);细胞移植后第5周两组猪心率无明显差异[(65.2±2.5)次/min对(50.3±2.0)次/min,P>0.05]。细胞移植后第3周时,给予微泵异丙肾上腺素后,实验组心率由(78.0±2.5)次/min上升至(103.0±2.1)次/min,对照组心率由(54.0±3.3)次/min上升至(64.0±2.0)次/min,实验组心率上升幅度明显高于对照组(33.2%对18.5%,P<0.05)。免疫荧光染色可见移植部位心肌细胞表达Tbx18蛋白。结论:将携带Tbx18的骨髓间充质干细胞移植入窦房结损毁猪模型的右室心外膜下,可以显著改善猪的心率,且对异丙肾上腺素具有良好的反应性。

Objective：To explore a new approach to treatment for bradyarrhythmia by transplanting mesenchymal stem cells（MSCs）carrying Tbx18 gene into the right subepicardial myocytes in pig models of sinoatrial node damage. Methods：Ten young pigs were randomly divided into test group and control group.Each group had 5 pigs.Build sinoatrial node damage model by burning the sinoatrial node with electrotome.Pigs in test group were injected with MSCs carrying Tbx18 while those in control group were injected with equal MSCs carrying green fluorescent protein（GFP）.Observe the heart rate and catecholamine-responsiveness of each group.Immunofluorescence analyses were used to detect the expression of Tbx8 in the myocardium from the injection site. Results：There was no significant difference in the heart rate between the test group and control group both before[（108.8±4.2）bpm vs.（106.6±6.8）bpm,P0.05]and after[（42.0±7.3）bpm vs.（43.4±5.1）bpm,P0.05]the sinus node was damaged.The heart rate was significantly higher in the test group than that in control group at the 2nd week after cell transplantation[（84.0±3.1）bpm vs.（53.6±2.5）bpm,P0.05].At the 3rd week after cell transplantation,the heart rate began to decrease in the test group but still higher than that in control group（all P0.05）.At the 5th week after cell transplantation,the heart rate of each group did not change obviously[（65.2±2.5）bpm vs.（50.3±2.0）bpm,P0.05].The heart rate in test group rose more than that in control group after the injection of isoproterenol by micropump at the 3rd week after cell transplantation.The heart rate rose from（78.0±2.5）bpm to（103.0±2.1）bpm in the test group while from（54.0±3.3）bpm to（64.0±2.0）bpm in the control group.The rising rate was 33.2% vs.18.5%（P0.05）.Immunofluorescence of cardiomyocytes in the transplanted site showed the expression of Tbx18 protein. Conclusion：Transplanting Tbx18 gene to the right subepicardial myocytes in pig models of sinoatrial node damage can obviously increase the heart rate and is sensitive to isoproterenol.