胰岛素抵抗大鼠缺血心肌Apelin及其受体的表达

Study of the expression of apelin and its recoptor in ischemic myocardium in insulin-resistant rats

目的探讨胰岛素抵抗（IR）大鼠在心肌缺血状态下心肌Apelin、APJ表达变化。方法24只雄性SD大鼠随机分IR组、IR＋缺血组、对照组，各8只。IR组及IR＋缺血组予高脂饲料喂养。对照组予以基础饲料喂养。判断IR造模成功后，给IR＋缺血组皮下注射异丙基肾上腺素1mg／d／kg，连续7d，制造缺血模型，其余两组注射等量生理盐水。取心肌组织real—time-PCR法测定APJ和ApelinmRNA表达水平。免疫组化测定Apelin多肽的阳性表达。结果Apelin：IR组较对照组表达升高（O．16±0．004比0．13±0．005，P〈0．05）；IR＋缺血组较对照组（0．10±0．002比0．13±0．005，P％0．05）及IR组（0．10±0．002比0．16±0．004，P％0．05）表达均明显降低。ApelinmRNA相对表达量比较：IR组较对照组表达量升高（5．89±0．36比4．40±0．24，P〈0，05），IR＋缺血组较IR组（5．89±0．36比2．66±0．17，P〈0．05）相对表达量均明显降低。APJmRNA相对表达量：IR组较对照组相对表达量明显升高（10．46±1．06比6．54±0．63，P〈0．05）；IR＋缺血组较IR组相对表达量降低（3．31±0．31比10．46±1．06，P〈0．05）。结论胰岛素抵抗大鼠中Apelin、APJ可能对心脏发挥保护作用，在心肌缺血时可反馈性抑制Apelin、APJ表达，减弱了对心脏的保护作用。

Objective To investigate the expression of apelin and its recoptor （APJ） in myocardium in insulin-resistant CIR rats with myocardial ischemia. Methods Totally 24 male SD rats were randomly divided into three groups： IR group, IRdischemia group, the control group （n= 8 each）. Rats in IR and IR--ischemia groups were fed with the high fat diet. Rats in control group were given the basic diet. The rat model of insulin resistance was assessed by fasting blood glucose （FBG）, fasting insulin （Fins） and insulin resistance index （HOMA-IR）. The rat model of myocardial ischemia was conducted by subcutaneous injection of isoprenaline 1 mg/kg per day in IR＋ ischemia group. The other groups were injected an equal volume of saline. The expression levels of apelin and APJ mRNA in myoeardium were determined by real-time-PCR. The positive expression of apelin polypeptide was detected by immunochemistry. Results Compared with the control group, the apelin average optical density was increased in IR group and was decreased in IR-b ischemia group 〈（0.16±0.004） vs. （0.13±0.005）, （0.10±0.002） vs. （0.13±0.0050）, both P〈0.053. There was a significant difference in apelin average optical density between IR group and IR＋ischemia group （0.16±0. 004） vs. （0.10 ± 0. 002）, P〈0.05. Compared with the control group, the relative expression of apelin mRNA was increased in IR group （5.89±0.36） vs. （4.40±0.24）,P〈0.05 The relative expression of apelin mRNA was decreased in IR＋ isehemia group as compared with IR group （2.66 ± 0.17） vs. （5.89 ± 0.36）, P〈 0.05 The APJ mRNA relative expression was increased in IR group as compared with control group and was decreased in IR＋ ischemia group as compared with lR group （10. 46±1. 06） vs. （6.54±0.63）, （3.31±0.31） vs. （10.46±1.06）, both P〈0.05. Conclusions The expressions of apelin and APJ are inhibited in insulin-resistant rats with myocardial ischemia, which attenuates their protective effects on myocardium.