依托咪酯对缺血再灌注大鼠心肌损伤的保护作用

Protective Effect of Etomidate on Myocardial Injury Induced by Ischemia-reperfusion in Rats

关键词:  依托咪酯  缺血再灌注  心损标记物  氧化应激

Key words:  etomidate  ischemia-reperfusion  cardiac injury markers  oxidative stress

摘要:

目的 探讨依托咪酯对缺血再灌注（ischemia reperfusion，I/R）大鼠心肌损伤的保护作用及其机制。方法 将大鼠随机分为5组：假手术组、模型组（I/R组）、I/R+依托咪酯（5 mg·kg^-1）组、I/R+依托咪酯（10 mg·kg^-1）组和I/R+依托咪酯（20 mg·kg^-1）组，采用冠状动脉结扎法建立I/R损伤模型。治疗组腹腔注射对应剂量的依托咪酯，假手术组和模型组给予等量生理盐水，每天给药1次，连续14 d。对大鼠心肌组织进行HE染色，观察心肌损伤情况；ELISA检测血清样本中心损标记物肌钙蛋白（cardiac troponin I，cTnI）、肌酸激酶同工酶（creatine kinase-MB，CK-MB）和肌红蛋白（myoglobin，Mb）表达水平，以及氧化应激指标丙二醛（malondialdehyde，MDA）、超氧化物歧化酶（superoxide dismutase，SOD）和乳酸脱氢酶（lactate dehydrogenase，LDH）的含量；TUNEL染色检测心肌凋亡情况；Western blotting检测心肌组织凋亡蛋白Bcl-2和Bax的表达情况，P65磷酸化及下游靶基因IL-1β和TNF-α的蛋白表达水平。结果 依托咪酯能改善I/R大鼠心肌损伤程度，并呈剂量依赖性地降低cTnI、CK-MB和Mb表达（P<0.05），增加SOD活性（P<0.05），降低LDH和MDA含量（P<0.05），下调Bax（P<0.05）、增加Bcl-2蛋白表达（P<0.05），降低心肌凋亡水平（P<0.05），抑制NF-κB P65的磷酸化（P<0.05）及下游靶基因IL-1β、TNF-α的蛋白表达水平（P<0.05）。结论 依托咪酯对I/R大鼠的心肌损伤起到保护作用，其机制与缓解氧化应激及抑制NF-κB P65的磷酸化相关。

Abstract:

OBJECTIVE To explore the protective effect and its mechanism of etomidate on myocardial injury in ischemia-reperfusion(I/R) model rats. METHODS Rats were randomly divided into five groups:sham operation group, model group(I/R group), I/R + etomidate(5 mg·kg^-1), I/R + etomidate(10 mg·kg^-1) and I/R + etomidate(20 mg·kg^-1) group. I/R injury model was established by coronary artery ligation. The treatment group received intraperitoneal injection of etomidate at the corresponding dose, and the sham operation group and the I/R group received the same amount of saline once a day for 14 consecutive days. HE staining was used to observe myocardial injury in rats. Cardiac injury markers[cardiac troponin I(cTnI), creatine kinase-MB(CK-MB), myoglobin(Mb)] and oxidative stress factor[malondialdehyde(MDA), superoxide dismutase (SOD), lactate dehydrogenase(LDH)] were detected by ELISA. TUNEL staining was used to detect myocardial apoptosis. Western blotting was used to detect the expression of apoptotic protein Bcl-2 and Bax, the phosphorylation of P65 and protein expression of its downstream target genes IL-1β and TNF-α. RESULTS Etomidate could improve the degree of myocardial injury in rats with I/R and decrease the expression of cTnI, CK-MB, Mb in dose-dependent manner(P<0.05), and increase SOD activity(P<0.05), decrease LDH, MDA content(P<0.05), down-regulate Bax(P<0.05) while up-regulate Bcl-2(P<0.05) protein expression, decrease myocardial apoptosis level(P<0.05), inhibit phosphorylation of NF-kB P65(P<0.05) and protein expression level of downstream target genes IL-1β and TNF-α(P<0.05). CONCLUSION Etomidate has protective effect on myocardial injury induced by I/R in rats, and its mechanism is related to alleviating oxidative stress and inhibiting phosphorylation of NF-kB P65.