经皮无创耳迷走神经刺激对阿霉素所致心脏毒性的保护作用

Protective effect of non-invasive transcutaneous vagal nerve stimulation against doxorubicin-induced cardiotoxicity

目的探讨经皮无创耳迷走神经刺激(tVNS)对阿霉素(DOX)所致心脏毒性的保护作用及潜在机制。方法将18只健康雄性Sprague-Dawley大鼠随机分为:DOX组、DOX+tVNS组和对照组,每组各6只。DOX组和DOX+tVNS组第0、7、14 d通过腹腔注射DOX(5 mg/kg),对照组腹腔注射等量生理盐水。DOX+tVNS组同时每天接受tVNS干预,每次30 min,连续刺激6周。6周后行超声心动图评估心脏功能,苏木素-伊红(HE)染色法检测心肌细胞的改变,酶联免疫吸附试验(ELISA)法测定血清氧化应激指标SOD和MDA水平,免疫荧光染色检测心肌组织白细胞介素-1β(IL-1β)的表达。结果 6周后,与对照组比较,DOX组大鼠心脏功能显著受损,左室射血分数(LVEF)和左室短轴缩短率(LVFS)明显降低,左室收缩末期内径(LVESd)和左室舒张末期内径(LVEDd)明显增大(P均<0.05);而tVNS干预可显著改善大鼠心脏功能,增加LVEF和LVFS,减小LVESd和LVEDd(P均<0.05)。DOX组大鼠心肌纤维排列紊乱,可见大量心肌细胞坏死和炎症细胞浸润,tVNS可明显减轻大鼠心肌细胞损伤。与对照组比较,DOX组SOD水平降低,MDA水平升高(P<0.05),而tVNS可明显逆转SOD和MDA异常改变(P<0.05)。促炎症因子IL-1β蛋白主要在DOX组中表达,在对照组中表达量最少,而tVNS能够显著下调DOX+tVNS组中IL-1β表达水平(P<0.05)。结论 tVNS对DOX所致心脏毒性具有保护作用,机制可能通过增强心脏抗氧化能力、抑制氧化应激水平和下调炎症细胞因子。

Objective To discuss the protective effect of non-invasive transcutaneous vagal nerve stimulation(tVNS)against doxorubicin(DOX)-induced cardiotoxicity and potential mechanism.Methods Male SD rats(n=18)were randomly divided into DOX group,DOX+tVNS group and control group(n=6).DOX group and DOX+tVNS group were given intraperitoneal injection of DOX(5 mg/kg)and control group was given equivalent normal saline on the 0 th,7 th and 14 th d.Meanwhile DOX+tVNS group was given tVNS intervention for 30 min each day for 6 weeks.After 6 weeks rat heart function was reviewed by using echocardiogram,and changes of cardiomyocytes were detected by using HE staining.The levels of SOD and MDA(serum oxidative stress indexes)were detected by using ELISA,and expression of IL-1βwas detected by using immunofluorescence staining.Results Rat heart function was damaged significantly,LVEF and left ventricular fraction shortening(LVFS)decreased significantly,and left ventricular end-systolic diameter(LVESd)and left ventricular end-diastolic inner diameter(LVEDd)increased significantly in DOX group(all P<0.05),rat heart function was significantly improved,LVEF and LVFS increased and LVESd and LVEDd decreased in DOX+tVNS group(all P<0.05)compared with control group after 6 weeks.There were disorganized arrangement of myocardial fibers and a lot of cardiomyocyte necrosis and inflammatory cell infiltration in DOX group,which were significantly relieved in DOX+tVNS group.SOD decreased and MDA increased in DOX group(P<0.05)and SOD increased and MDA decreased in DOX+tVNS group(P<0.05)compared with control group.The expression of IL-1βprotein(a pro-inflammatory cytokines)was observed in DOX group,was the least in control group and was significantly down-regulated in DOX+tVNS group(P<0.05).Conclusion Non-invasive tVNS has a protective effect against DOX-induced cardiotoxicity,and the mechanism may be related to improving cardiac antioxidant capacity,inhibiting oxidative stress level and down-regulate inflammatory cytokines.