短期颈动脉压力感受器电刺激对犬心肌缺血再灌注损伤的影响

摘要

Objective To evaluate the effect of short-term carotid baroreceptors stimulation (CBS) on myo-cardial ischemia reperfusion injury (IRI). Methods Thirty-six adult dogs were randomly divided into three groups (n=12):Sham group, ischemia reperfusion group (I/R group) and carotid baroreceptors stimulation group (CBS group). Dogs in I/R group and CBS group were given respectively 1 h left anterior descending coronary artery (LAD) ligation and 6 h reperfusion to complete IRI models, while dogs in Sham group received only threading. In CBS group, high frequency stimulations were performed on the right carotid sinus from 2 h before myocardial ischemia to the end of ex-periment (stimulation parameters: frequency 50 Hz, pulse width: 0.5 ms, stimulation intensity adjusted according to blood pressure so as to keep the blood pressure down 10%before stimulation). Heart rate (HR) and mean arterial pres-sure (MAP) were recorded before ischemia, 15 min, 30 min and 60 min after ischemia, and 0.5 h, 2 h and 6 h after re-perfusion. Six dogs from each group were randomly selected to test the area of myocardial ischemia and myocardial in-farction by Evans blue-triphenyl tetrazolium chloride (TTC) double-staining method at 6h after reperfusion. Internal jugular vein blood of the rest 6 dogs from each group were collected at 6 h after reperfusion, and serum TNF-α, IL-1βand IL-6 were tested by ELISA. After blood collection, we quickly took out the ischemic myocardial tissues to detect the infiltration of neutrophil cells through myeloperoxidase (MPO) activity observation. Results Compared with Sham group, the infarction area, MPO activity, serum levels of TNF-α, IL1-β and IL-6 of I/R group and CBS group were increased (P<0.05);compared with IR group, all the above indexes of CBS group were lower (P<0.05). Conclusion Carotid baroreceptors stimulation can reduce myocardial ischemia reperfusion injury. And the mecha-nism may be associated with the suppression of neutrophil infiltration and inflammatory reaction.%目的：评价短期颈动脉压力感受器电刺激(Carotid baroreceptors stimulation，CBS)对犬心肌缺血再灌注损伤的影响。方法36只成年杂种犬随机分为三组(n=12)：假手术组(Sham组)，缺血再灌注组(I/R组)和颈动脉压力感受器刺激组(CBS组)。I/R组和CBS组分别结扎左冠脉前降支1 h和再灌注6 h完成心肌缺血再灌注损伤模型，Sham组只穿线不结扎冠脉。CBS组在心肌缺血前2 h对右侧颈动脉窦开始进行高频电刺激，一直持续到实验结束，刺激参数：频率50 Hz，脉宽0.5 ms，刺激强度随血压进行调整，以保持血压较刺激前下降10%。于缺血前(基础状态)、缺血15 min、30 min、60 min和再灌注0.5 h、2 h、6 h时记录心率(HR)和平均动脉压(MAP)。各组随机抽取6只犬于于再灌注6 h后采用依文斯兰-氯化三苯基氮唑(TTC)双染色法检测心肌缺血和心肌梗死面积。各组剩余6只犬于再灌注6 h分别经颈内静脉采血，采用ELISA法检测血清TNF-α、IL-1β、IL-6。采血后，迅速取出缺血区心肌组织，检测髓过氧化物酶(MPO)活性观察中性粒细胞浸润情况。结果与Sham组比较，I/R组和CBS组心肌梗死面积，MPO活性，血清TNF-α、IL-1β、IL-6含量升高(P<0.05)；与I/R组比较，CBS组心肌梗死面积，MPO活性，血清TNF-α、IL-1β、IL-6含量降低(P<0.05)。结论短期颈动脉压力感受器电刺激可减轻犬心肌缺血再灌注损伤，其机制与抑制中心粒细胞向缺血组织浸润以及抑制炎症反应有关。