摘要:
目的 观察黄芪甲甙对急性心肌梗死模型大鼠心脏的保护作用,并探讨其可能的分子机制.方法 将45只Wistar大鼠随机分为假手术组、模型组和黄芪甲甙组,每组15只.模型组和黄芪甲甙组大鼠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,假手术组大鼠只穿线不接扎;造模24 h后,黄芪甲甙组大鼠腹腔注射黄芪甲甙20 mg·kg-1·d-1,假手术组、模型组大鼠腹腔注射相同体积的羧甲基纤维素钠,每日1次,连续2周.分别于造模前、造模后即刻及给药1、3、7、14d描记肢体Ⅱ导联心电图,观察ST段变化.给药2周后,检测各组大鼠左心室舒张末期内径(LVDD)、左心室收缩末期内径(LVDS)、左心室舒张末期容积(LVEDV)、左心室收缩末期容积(LVESV)、左心室短轴的缩短率(LVFS)及左心室射血分数(LVEF);应用酶联免疫吸附试验法检测各组大鼠血清肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)及核转录因子-κB(NF-κB)水平,并检测血浆一氧化氮(NO)水平;实时荧光定量聚合酶链反应检测各组大鼠心肌组织中Toll样受体(TLR)2、TLR4、核苷酸结合寡聚化结构域(NOD)1、NOD2及内皮型一氧化氮合酶(eNOS) mRNA的表达.结果 造模过程中,假手术组、模型组、黄芪甲甙组大鼠分别死亡0、4、2只.模型组和黄芪甲甙组大鼠造模后即刻及给药后1、3、7、14 d ST段值均显著高于假手术组(P<0.01).黄芪甲甙组大鼠给药后3、7、14dST段值均显著低于模型组(P<0.05).与假手术组比较,模型组和黄芪甲甙组大鼠LVDD、LVDS显著扩大(P<0.01),LVEDV、LVESV显著增加(P<0.01),LVFS、LVEF显著下降(P<0.01);血清IL-1β、1L-6、TNF-α水平和心肌组织中TLR2、TLR4、NOD1、NOD2 mRNA水平显著增加(P<0.01);血浆NO水平显著降低(P<0.05).模型组大鼠血清NF-κB水平高于假手术组(P<0.01),心肌组织中eNOS mRNA表达低于假手术组(P<0.05).黄芪甲甙组与假手术组大鼠血清NF-κB水平和心肌组织中eNOS mRNA表达比较差异无统计学意义(P<0.05).与模型组比较,黄芪甲甙组大鼠LVDD、LVDS显著缩小(P<0.05),LVEDV、LVESV显著下降(P<0.05),LVFS、LVEF显著增加(P<0.05);血清IL-1β、IL-6、TNF-α、NF-κB水平和心肌组织中TLR2、TLR4、NOD1、NOD2 mRNA表达显著降低(P<0.05);血浆NO水平和心肌组织中eNOS mRNA表达显著升高(P<0.05).结论 黄芪甲甙对急性心肌梗死大鼠心脏具有保护作用,其机制可能与激活eNOS信号系统和抑制TLR信号途径有关.%Objective To evaluate the cardio protective effect of astragaloside in rats with acute myocardial infarction and investigate the potential molecular mechanisms.Methods Forty-five Wistar rats were randomly divided into sham operation group,model group and astragaloside group,with 15 rats in each group.The acute myocardial infarction model was prepared by permanently occluding the left anterior descending artery in the model group and the astragaloside group,while the rats in the sham operation group were threaded only.Twenty-four hours after operation,the rats in the astragaloside group received astragaloside 20 mg · kg-1 · d-1 by intraperitoneal injection,once a day for two weeks.The rats in sham operation group and model group received isodose carboxymethylcellulose sodium by intraperitoneal injection,once a day for two weeks.Electrocardiogram was recorded to observe the changes of ST segment before ligation,after ligation immediately,1,3,7,14 d after intervened by astragaloside.Echocardiography was used to detect the left ventricular internal diameter at end-diastole (LVDD),left ventricular internal diameter at end-systole (LVDS),left ventricular end diastohc volume (LVEDV),left ventricular end systolic volume (LVESV),left ventricular fractional shortening (LVFS),left ventricular ejection fraction (LVEF).The levels of tumor necrosis factor alpha (TNF-α),interleukin (IL)-1 β,IL-6,nuclear factor-κB (NF-κB) in serum were measured by enzyme linked immunosorbent assay and the level of nitric oxide(NO) in plasma was measured by reagent kid.The expressions of toll-like receptor(TLR) 2,TLR4,nucleotide binding oligomerization do main(NOD) 1,NOD2,endothelial nitric oxide synthase (eNOS) mRNA were detected by quantitative real-time polymerase chain reaction.Results During the operation,there was 0,4,2 dead rats in the sham operation group,model group and astragaloside group.The ST segment in the model group and astragaloside group was higher than that in the sham operation group after operation immediately,1,3,7,14 d after intervented by astragaloside(P < 0.01).The ST segment in the astragaloside group was lower than that in the model operation group at the time of 1,3,7,14 d after intervented by astragaloside(P < 0.05).Compared with the sham operation group,the LVDD,LVDS,LVEDV,LVESV increased (P < 0.01),LVFS,LVEF decreased (P < 0.01),the levels of TNF-α,IL-1β,IL-6 and the expression of TLR2,TLR4,NOD1,NOD2 mRNA in cardiac muscle tissue were higher in the model group and astragaloside group (P < 0.01),the level of NO was lower (P < 0.05).The level of serum NF-κB in the model group was higher than that in the sham operation group(P <0.01),the expression of the eNOS mRNA in cardiac muscle tissue was lower than that in the sham operation group(P < 0.05).There was no significant difference in the level of serum NF-κB and the expression of the eNOS mRNA in cardiac muscle tissue between the astragaloside group and sham operation group (P < 0.05).Compared with the model group,in the astragaloside group the LVDD,LVDS,LVEDV,LVESV decreased (P < 0.05),but LVFS,LVEF increased (P < 0.05),the levels of TNF-o,IL-1 β,IL-6,NF-κB and the expression of TLR2,TLR4,NOD 1,NOD2 mRNA in cardiac muscle tissue were lower(P < 0.05),the level of NO and the expression of the eNOS mRNA in cardiac muscle tissue were higher(P < 0.05).Conclusion Astragaloside has protective effect against to acute myocardial infarction induced injury by decreasing the expression of TLR signal path and activating eNOS signaling.