犬窦房结组织带蒂自体移植治疗完全性房室传导阻滞疾病的实验研究

摘要

目的将窦房结组织带蒂移植入自体心室中，通过观察带蒂移植的窦房结组织能否存活并与心室肌建立细胞连接；射频消融希氏束建立完全性房室传导阻滞动物模型，观察其能否起搏心室；为完全性房室传导阻滞探索新的治疗思路和方法。方法健康家犬10只，随机分为移植组和对照组，每组各5只。安置临时心外膜起搏导线后，将犬窦房结组织带蒂移植于实验组自体右心室心外膜下，对照组仅切除窦房结组织，于第1、2、3、4周观测体表心电图变化。4周后射频消融希氏束，建立完全性房室传导阻滞动物模型。建立模型后对两组动物经股静脉微泵注射异丙肾上腺素（ISO），观察心率变化。并观测带蒂移植后的窦房结组织学及超微结构变化。结果体表心电图无明显变化。射频消融希氏束后，移植组和对照组均表现为完全性房室传导阻滞心电图，两组室性心率无明显差别（P>0.05）。注射ISO后，两组室性心率改变不明显（P>0.05）。带蒂移植的窦房结组织可以存活，并与心室肌细胞建立桥粒连接，但细胞连接数目不多，不能起搏心室。结论带蒂移植入自体心室的窦房结组织细胞可以和心肌细胞建立细胞连接。%Objective To observe the changes of surface ECG and cell couplings between sinoatrial node cells and myocardial cells following transplantion of pedicled autologous sinoatrial node tissue graft into the right ventricle of a canine model of complete atrioventricular block. Methods Ten healthy dogs were randomized into transplantation group and control group. Pedicled autologous sinoatrial node tissue grafts were transplanted into the right ventricle in the transplantation group, while the sinoatrial nodes were only excised in the control group after placement of temporary myocardial pacing wires. The changes of surface ECG were observed at 1, 2, 3 and 4 weeks postoperatively. At 4 weeks, complete atrioventricular block was induced in the dogs by radiofrequency ablation of the His bundle. The heart rate of the dogs in both groups were recorded after the injection of isoproternol (ISO) from the femoral vein, and the transplanted tissue graft was observed under optical and transmission electron microscopes. Results No significant changes occurred in the surface ECG. All the dogs showed ECG waveforms specific of complete heart block after the ablation, and the ventricular heart rates were similar between the two groups (P>0.05). The ventricular heart rate did not undergo obvious changes after ISO injection (P>0.05). The transplanted pedicled autologous sinoatrial node survived in the dogs and the sinoatrial node cells established desmosome junctions with the myocardial cells, but the number of junctions was not sufficient to support heart pacing. Conclusions Desmosome junction can occur between ventricular myocardial cells and sinoatrial node cells at the edge of transplanted pedicled autologous sinoatrial node tissue.