绝对不应期电刺激对慢性心力衰竭犬自主神经活性调节的影响及机制研究

The mechanism of electric stimulation during absolute refractory period in treating patients with chronic heart failure remains unclear. Previous studies performed by the applicant team found that cardiact resynchronization therapy（CRT） has a significant impact on autonomic nervous function in canine heart failure models. We propose on the bases of domestic and foreign documents that electric stimulation during absolute refractory period can boost cardiac vagus nerve efferent impulse and rebalance autonomic nervous function by acting on the cardiac mechanoreceptor. In the present study,we intend to establish the canine heart failure model by atrial tachypacing in order to compare the effects of electric stimulation during absolute refractory period and CRT on autonomic nervous function,to observe the effects of this two kinds of treatment on heart function and hemodynamics in denerved canine heart and to detect the gene expression level by molecular biology techniques at different time points after treatment for heart failure，further analyzing the relationship of altered autonomic nervous function and heart failure related genes.The project is to delve into the mechanism of absolute refractory period electric stimulation in the treatment of chronic heart failure.

绝对不应期电刺激治疗慢性心力衰竭的机制尚不清楚。申请人团队前期进行慢性心力衰竭犬心脏再同步治疗（CRT）研究中发现CRT对衰竭心脏自主神经功能有显著影响。综合国内外文献后我们提出绝对不应期电刺激治疗慢性心力衰竭的机制可能与绝对不应期电刺激激活心脏机械感受器后增强心脏迷走神经活性输出，恢复自主神经平衡有关。本项目拟通过建立扩张型心肌病犬模型，首先分别进行绝对不应期电刺激和CRT治疗，观察两种方法对衰竭心脏的自主神经功能变化的影响。其次，对慢性心力衰竭犬行去自主神经手术后，再分别进行绝对不应期电刺激和CRT治疗，观察两种治疗对心功能和血流动力学的影响。最后，通过分子生物学技术在治疗后不同时间点对心力衰竭相关基因表达水平进行检测，分析绝对不应期电刺激后自主神经功能变化与心力衰竭相关基因表达的关系。本项目为深入探讨绝对不应期电刺激治疗慢性心力衰竭的机制提供新线索。

绝对不应期电刺激治疗慢性心力衰竭的机制尚不清楚。本项目通过建立扩张型心肌病犬模型，研究选取17只健康的比格犬，分为假手术组，心力衰竭对照组和CCM治疗组。心力衰竭对照组和CCM治疗组通过右颈外静脉植入起搏导线，并放置超速起搏器快速起搏。经过6周快速起搏，成功制备心衰模型。6周后CCM组植入CCM1周，心衰对照组停止超速起搏1周。过程中均留取血流动力学指标、超声心动图和心电图。通过解剖进行病理分析。选取三组心肌样本，进行代谢组学检测，以评估三组的代谢组学概况。研究发现 超速起搏 6 周后，心衰对照组和 CCM 治疗组各心腔扩大[左室收缩末容积(LVESV)：心衰组 7.2±2.16 ml vs 23.6± 8.88 ml, CCM组11.2±2.94 ml vs 24.0±4.18 ml; 左室舒张末容积(LVEDV):心衰组 22.8±3.27 ml vs 36.8±9.42 ml，CCM组 26.2±3.83 ml vs 38.4±7.09 ml]，LVEF值较术前明显下降(心衰组67.2±8.23 vs 36.4±5.68, CCM组 57.8±7.73 vs 38.4±2.88)，心力衰竭模型建模成功。血流动力学显示，应用CCM治疗1小时后CCM组血流动力学指标明显改善(动脉收缩压: 144.27±7.72 mmHg vs 112.1±12.03 mmHg, P=0.001; 平均动脉压: 111.74±8.315 mmHg vs 81.36±4.48 mmHg, P =0.001; 左室内压最大上升速率: 3649.98± 328.70 mmHg vs 2062.95± 257.36 mmHg, P<0.001)。1周后复查超声, CCM治疗组 LVEF上升较心衰对照组明显(61.8±3.27 vs 48.8±7.12，P=0.009)。病理提示CCM治疗对于心衰导致的左室重构有一定改善作用。通过分析牛磺酸代谢通路差异代谢物在健康对照、心衰组和CCM组的变化，发现经过CCM组较心衰组相关差异物水平更接近健康组的水平。说明CCM可能通过改变牛磺酸代谢通路影响心衰代谢。