大鼠缺血预处理对心肌保护作用及脂联素表达的影响

Effect of ischemic preconditioning on cardioprotection and expression of adiponectin in rat model

目的探讨心肌缺血预处理(IPC)对成年和老年大鼠的心功能及心肌组织和血浆中脂联素表达的影响。方法取成年和老年大鼠各85只,将IPC成功的成年和老年大鼠各50只中,随机各取40只为IPC组,另10只再建心肌梗死(M1)模型为IPC-M1组;只穿线不阻断血流的成年和老年大鼠各30只中,随机各取20只作为假手术组,另10只建MI模型为单纯MI组。假手术组及IPC组又分别于IPC后0、6、12和24h 4个时间点观察。将未结扎冠状动脉的成年和老年大鼠各5只作为对照组。用M型超声检测心功能,Masson's Trichrome染色,测量MI面积,免疫组织化学法和RT-PCR法测心肌组织脂联素蛋白和mRNA的表达,用ELISA法检测血浆脂联素含量。结果老年大鼠IPC-MI组存活率显著低于单纯MI组和对照组(P<0.05),而成年大鼠3组生存率无变化(P>0.05)。成年大鼠IPC-MI组短轴缩短率较单纯MI组明显升高,MI面积显著减小(P<0.05);与假手术组比较,IPC组6和12h心肌组织脂联素mRNA表达明显升高(P<0.05),血浆脂联素在0、6和12h显著升高(P<0.05)。老年大鼠IPC组各时间点心肌组织脂联素mRNA表达与假手术组无显著差异,血浆脂联素24 h明显升高(P<0.05)。结论成年大鼠IPC后心肌组织和血采脂联素表达均升高,心功能改善,老年大鼠脂联素变化不明显,提示脂联素参与成年大鼠IPC发挥的心肌保护作用。

Objective To investigate the effect of myocardial ischemia preconditioning （IPC） on heart function and expression of adiponectin in the young and old rat models. Methods Young and old rat IPC and MI models were set up. The expression of adiponectin at 0 h,6 h,12 h and 24 h after IPC was examined by immunohistochemistry,quantitative real time RT-PCR and ELISA. Results In young rats,IPC increased left ventricular fractional shortening and reduced infarct size （P〈 0.05） compared with control MI model. In old rats,however,the mortality in rats with MI after IPC was higher than those with only MI. Compared with sham operation group,the plasma level of adiponectin increased significantly 0 h,6 h and 12 h after IPC （P〈 0.05）. However,in old rats,the expression of adiponectin mRNA and protein after IPC showed no difference with those in control group, and the plasma concentration increased until 24 h after IPC. Conclusion In young rats IPC improved heart function and increased the expression of adiponectin in myocardium and plasma, but in old rats,its effect on expression of adiponectin weakened, suggesting that adiponecitn may play a role in protective effect of IPC only in young rats.