丹皮酚对急性心肌梗死大鼠氧化应激和内皮型一氧化氮合酶信号通路的影响

摘要

目的 观察丹皮酚对急性心肌梗死模型大鼠心脏的保护作用,并探讨可能的分子机制.方法 将50只大鼠随机分为对照组、模型组及丹皮酚低、中、高剂量组,每组10只.丹皮酚低、中、高剂量组大鼠分别腹腔注射丹皮酚注射液4、8、16 mg·kg-1·d-1.对照组、模型组大鼠腹腔注射生理盐水1.6 mL·kg-1·d-1,连续给药14 d.末次给药后30 min,除对照组大鼠外,其余各组大鼠均通过永久性结扎大鼠左冠状动脉前降支制作急性心肌梗死模型.并于冠状动脉结扎后6h,检测血浆肌酸激酶(CK)、肌酸激酶同工酶(CKMB)、乳酸脱氢酶(LDH)、心肌肌钙蛋白T(cT-nT)、一氧化氮(NO)、8-异前列腺素水平,及心肌组织中丙二醛(MDA)和超氧化物歧化酶(SOD)水平,同时实时定量反转录-聚合酶链式反应检测心肌组织中内皮型一氧化氮合酶(eNOS) mRNA表达.结果 与对照组比较,模型组及丹皮酚低、中、高剂量组大鼠心电图中ST段显著升高(P＜0.01),血浆中CK、CKMB、LDH、cTnT及心肌组织中MDA水平均显著增高(P＜0.05),而血浆中NO含量、SOD活力和心肌组织中eNOS mRNA表达水平显著降低(P＜0.05).与模型组比较,丹皮酚中、高剂量组大鼠心电图中ST段显著降低(P＜0.05),血浆中CK、CKMB、LDH、cTnT、8-异前列腺素和心肌组织中MDA水平显著下降(P＜0.05),同时血浆中NO含量和心肌组织中SOD活性、eNOS mRNA表达显著增加(P＜0.05);丹皮酚低剂量组与模型组大鼠比较,除CKMB显著下降外(P＜0.05),其余均无明显变化(P＞0.05).与丹皮酚低剂量组比较,丹皮酚高剂量组大鼠心电图中ST段显著降低(P＜0.05),血浆中CK、CKMB、LDH、cTnT、8-异前列腺素及心肌组织中MDA水平显著降低(P＜0.05),而血浆中NO含量、SOD活力和心肌组织中eNOSmRNA表达显著增高(P＜0.05);丹皮酚中剂量组与低剂量组大鼠比较,除LDH、cTnT、SOD活力、8-异前列腺素外,其余指标均有显著变化(P＜0.05).与丹皮酚中剂量组比较,丹皮酚高剂量组大鼠心电图中ST段显著降低(P＜0.05),血浆中CK、CKMB、LDH、cTnT、8-异前列腺素及心肌组织中MDA水平显著降低(P＜0.05),心肌组织中eNOS mRNA表达显著升高(P＜0.05),而血浆中NO含量和心肌组织中SOD活力变化不明显(P＞0.05).结论 丹皮酚对急性心肌梗死大鼠心肌具有保护作用,其作用可能与激活eNOS信号系统和抑制氧化应激有关.%Objective To observe the cardioprotective effect of paeonol in acute myocardial infarction rats and explore the potential molecular mechanisms of this effect.Methods Fifty rats were randomly divided into control group,model group,low dose paeonol group,middle dose paeonol group and high dose paeonol group,with 10 rats in each group.The rats in low dose paeonol group,middle dose paeonol group and high dose paeonol group were given paeonol injection intraperitoneally (4,8,16 mg· kg-1 · d-1 respectively)for 14 days;the rats in the control group and the model group were injected saline (1.6 mL · kg-1 · d-1) intraperitoneally for 14 days.The acute myocardial infarction model was established by occluding the left anterior descending artery permanently in all rats except control group at 30 min after the last administration.The levels of casein kinase(CK),isoenzyme of creatine kinase (CKMB),lactate dehydrogenase (LDH),cardiac troponin T (cTnT),nitric oxide (NO),8 isoprostane in plasma and malondialdehyde (MDA),superoxide dismutase (SOD) in myocardium were measured at 6 h after occluding the coronary artery.The expression of endothelial nitric oxide synthase (eNOS) mRNA were detected by quantitative real-time polymerase chain reaction.Results Compared with the control group,the ST segment elevated more significantly (P ＜ 0.01),the levels of CK,CKMB,LDH,cTnT,8-isoprostanes in plasma and MDA in myocardium increased more obviously in the model group,low dose paeonol group,middle dose paeonol group and high dose paeonol group (P ＜ 0.05);the NO content in plasma and SOD activity,the expression of eNOS mRNA in myocardium were markedly decreased(P ＜ 0.05).Compared with the model group,the ST segment depressed more significantly (P ＜ 0.05),the levels of CK,CKMB,LDH,cTnT,8-isoprostanes in plasma and MDA in myocardium decreased obviously in the medium dose paeonol group and high dose paeonol group (P ＜ 0.05);the NO content in plasma and SOD activity,the expression of eNOS mRNA in myocardium were significantly increased(P ＜ 0.05).The level of CKMB in plasma of rats in low dose paeonol group was significantly lower than that in the model group(P ＜0.05);there was no statistic difference in the other indexes between the low dose paeonol group and model group(P ＞0.05).Compared with the low dose paeonol group,the ST segment depressed more significantly(P ＜ 0.05),the levels of CK,CKMB,LDH,cTnT in plasma and MDA in myocardium decreased more obviously in the high dose paeonol group(P ＜0.05);the NO content in plasma and SOD activity,the expression of eNOS mRNA in myocardium were markedly increased (P ＜ 0.05).There was no significant changes in the levels of LDH,cTnT,8-isoprostanes and SOD activity between the low dose paeonol group and middle dose paeonol group (P ＞ 0.05),while the other indexes had significant changes (P ＜ 0.05).Compared with the middle dose paeonol group,the ST segment depressed more significantly (P ＜ 0.05),the levels of CK,CKMB,LDH,cTnT in plasma and MDA in myocardium decreased obviously in the high dose paeonol groups (P ＜ 0.05);the expression of eNOS mRNA in myocardium was obviously increased(P ＜ 0.05);there were no significant changes in NO content in plasma and SOD activity in myocardium between middle dose paeonol group and high dose paeonol group(P ＞ 0.05).Conclusions Paeonol has a protective effect on myocardium in rats with acute myocardial infarction.This effect may be relate with the activation of eNOS signal sysytem and inhibition of oxidative stress.