摘要
目的:观察黄芪甲苷(AS-Ⅳ)对大鼠心肌局部缺血再灌注(I/R)损伤的改善作用及其对PI3K/Akt/mTOR信号通路的影响,阐明AS-Ⅳ对心肌I/R损伤的保护作用及可能机制。方法:选择60只雄性SpragueDawley大鼠,采用阻断左冠状动脉前降支血流30min再灌注120min的方法制备局部I/R模型,随机分为模型组(等体积生理盐水)、AS-Ⅳ组(于再灌注前5min静脉注射10mg·kg-1 AS-Ⅳ)、PI3K抑制剂Wortmannin(WOR)组(于再灌注前10min静脉注射0.6mg·kg-1 WOR)和AS-Ⅳ+WOR组(于再灌注前5、10min依次静脉注射10mg·kg-1 AS-Ⅳ和0.6mg·kg-1 WOR)。同时选取15只同周龄大鼠作为正常对照(对照组)。分析各组大鼠I/R后的心脏质量、心肌缺血程度和梗死程度及心功能情况[左室收缩期平均压(LVSP)、舒张末期压力(LVEDP)、短轴缩短率(FS)和射血分数(EF)];采用Western blotting法检测心肌梗死区Akt及mTOR磷酸化(p-Akt和p-mTOR)水平,特异性荧光探针DHE染色分析心肌活性氧自由基水平。结果:与对照组比较,模型组大鼠心肌缺血程度、梗死程度、LVEDP、心肌p-Akt/Akt和p-mTOR/mTOR及活性氧自由基水平均升高(P<0.05),LVSP、FS和EF均降低(P<0.05)。与模型组比较,AS-Ⅳ组大鼠心肌缺血程度、梗死程度、LVEDP及活性氧自由基水平均降低(P<0.05),心肌p-Akt/Akt、p-mTOR/mTOR及LVSP、FS和EF均升高(P<0.05);与AS-Ⅳ组比较,WOR组和AS-Ⅳ+WOR组大鼠心肌缺血程度、梗死程度、LVEDP及活性氧自由基水平均升高(P<0.05),心肌p-Akt/Akt、p-mTOR/mTOR及LVSP、FS和EF均降低(P<0.05)。结论:AS-Ⅳ对心肌I/R损伤有改善作用,可降低心肌梗死及氧化应激程度并提高心功能,其机制可能通过激活PI3K/Akt/mTOR信号通路发挥作用。
Objective To observe the improvement effects of astragaloside Ⅳ （AS-Ⅳ）on the myocardial focal ischemia-reperfusion （I/R）injury and its influence in PI3K/Akt/mTOR pathway,and to clarify the protective effect of AS-Ⅳ on myocardial I/R inj ury and the possible mechanisms.Methods The left main coronary arteries of 60 Sprague-Dawley rats were occluded for 30 min followed by a 120-min reperfusion to induce I/R model.The rats with I/R inj ury were randomly divided into model group （normal saline）, AS-Ⅳ group （intravenous inj ection of 10 mg·kg-1 AS-Ⅳ 5 min before reperfusion）,PI3K inhibitor Wortmannin （WOR）group （intravenous injection of 0.6 mg·kg-1 WOR 10 min before reperfusion）and AS-Ⅳ＋WOR group （intravenous injection of 10 mg·kg-1 AS-Ⅳ and 0.6 mg·kg-1 WOR 5 and 10 min before reperfusion,respectively）.15 age-matched SD rats were chosen as control group.The heart mass,degrees of infarction and ischemia and cardiac function ,including left ventricular systolic mean pressure （LVSP）,end-diastolic pressure （LVEDP）,fractional shortening （FS）and ej ection fraction （EF）,of the rats in all groups were analyzed. Western blotting method was used to measure the phosphorylation levels of Akt and mTOR（p-Akt and p-mTOR）.The specific fluorescent probe DHE staining was employed to detect the myocardial reactive oxygen species levels. Results Compared with control group, the degrees of infarction and ischemia, LVEDP, myocardial levels of p-Akt/Akt, p-mTOR/mTOR and reactive oxygen species levels of the rats were increased （P〈0.05）.and the levels of LVSP,FS and EF were decreased in model group （P〈0.05）. Compared with the model group,the degrees of infarction and ischemia,LVEDP and reactive oxygen species level were decreased （P〈0.05）,while the levels of p-Akt/Akt,p-mTOR/mTOR LVSP, FS and EF of all rats in AS-Ⅳ group were increased （P〈0.05）.Compared with AS-Ⅳ group,the degrees of infarction and ischemia,LVEDP and reactive oxygen species levels
出处
《吉林大学学报（医学版）》
CAS
CSCD
北大核心
2014年第5期991-996,I0004,共7页
Journal of Jilin University：Medicine Edition
基金
吉林省发改委专项基金资助课题(2012747)
