红景天苷对大鼠缺血再灌注损伤心肌Akt/GSK-3β作用的研究

Effect of salidroside on Akt/GSK-3β of myocardium with ischemia-reperfusion injury in rats

目的缺血预处理和后处理能够产生一定的心肌保护效应。观察红景天苷对大鼠心肌缺血-再灌损伤的保护作用,并探讨其保护作用的机制。方法将SD大鼠按随机数字表法分为6组,每组6只:假手术组、心肌缺血-再灌注模型组、红景天苷预防组、红景天苷治疗组、红景天苷预防组+磷脂酰肌醇-3-激酶(PI3K)特异性抑制剂LY294002组(LY294002预防组)、红景天苷治疗组+PI3K特异性抑制剂LY294002组(简称LY294002治疗组)。红景天苷预防组和LY294002预防组于造模前给予红景天苷12 mg/kg腹腔注射1次/d,连续3 d;LY294002治疗组于再灌注即刻给予红景天苷12 mg/kg腹腔注射;假手术组和心肌缺血-再灌注模型组均给予等量等渗盐水腹腔注射;LY294002预防组和LY294002治疗组于冠状动脉左前降支结扎前35 min腹腔注射0.3 mg/kg体重的PI3K特异性抑制剂LY294002。采用免疫细胞化学法检测细胞内Akt、p-Akt、GSK-3β、p-GSK-3β的分布与变化,Western blot测定细胞内Akt、GSK-3β蛋白表达水平变化及磷酸化状态。结果假手术组、心肌缺血-再灌注模型组、LY294002预防组、LY294002治疗组p Akt/Akt值(0.246±0.002、0.457±0.012、0.303±0.005、0.361±0.019)较红景天苷预防组(0.857±0.014)、红景天苷治疗组(0.683±0.009)均明显降低(P<0.05)。假手术组、心肌缺血-再灌注模型组、LY294002预防组、LY294002治疗组p GSK-3β/GSK-3β值(0.137±0.004、0.380±0.026、0.148±0.013、0.267±0.050)较红景天苷预防组(0.944±0.045)、红景天苷治疗组(0.895±0.043)亦明显降低(P<0.05),而红景天苷预防组与红景天苷治疗组组间比较差异无统计学意义(P>0.05)。结论红景天苷可增加缺血-再灌注心肌中Akt/GSK-3β的蛋白表达及磷酸化,增强对缺血-再灌注损伤心肌保护作用。

Objective Ischemic preconditioning and postconditioning can provide certain protection for myocardium. The article was designed to observe the protective effect of salidroside on myocardial ischemia reperfusion injury（ MIRI） and explore its mechanisms. Methods SD rats were randomly divided into 6 groups with 6 rats for each： sham operation group（ S group）,ischemiareperfusion group（ I/R group）,salidroside preventive group（ salidroside treatment followed by ischemia-reperfusion）,salidroside treatment group（ ischemia-reperfusion followed by salidroside treatment）,salidroside preventive ＋ LY group（ LY294002 preventive group）and salidroside treatment ＋ LY group（ LY294002 treatment group）. Salidroside was administered once a day for three days before modelling in both salidroside preventive group and LY294002 preventive group; while salidroside was given immediately after the reperfusion in both salidroside treatment group and LY294002 treatment group. The same volume of NS was administered only to the rats in S group and I/R group. The PI3 K inhibitor（ LY294002） was given additionally 35 mins before LAD ligation in both LY294002 preventive group and LY294002 treatment group. All injections were given intraperitoneally. Akt,p-Akt,GSK-3β and p-GSK-3β in myocardium were examined with immunocytochemical method in all groups. The protein expression and phosphorrylation status of Akt/GSK-3β were determined by western blot. Results The levels of Akt/GSK-3βin myocardium of S group（ 0. 246 ± 0. 002）,I/R group（ 0. 457 ±0. 012）,LY294002 preventive group（ 0. 303 ± 0. 005）,LY294002 treatment group（ 0. 361 ± 0. 019） decreased significantly in comparison to those of salidroside preventive group（ 0. 857 ± 0. 014） and salidroside treatment group（ 0. 683 ± 0. 009）（ P〈0. 05）. The levels of p- GSK-3β/GSK-3βin myocardium of S group（ 0. 137 ± 0. 004）,I/R group（ 0. 380 ± 0. 026）,LY294002 preventive group（ 0. 148 ±0. 013）,LY294002 treatment group（ 0. 267 ± 0. 050） also decreased significantly in comparison to those of salidroside preventive group（ 0. 944 ± 0. 045） and salidroside treatment group（ 0. 895 ± 0. 043）（ P〈0. 05）. As to the comparison between salidroside preventive group and salidroside treatment group,there was no significant difference（ P〈0. 05）. Conclusion The result indicates that salidroside protects myocardium against MIRI in rats. The cardioprotective effect might be associated with the increased protein expression and the phosphorylation rate of Akt/GSK-3β.