下调心肌CD36的表达对肥胖小鼠心肌活性氧簇生成的影响

Effects of Cardiac CD36 Inhibition on Generation of Myocardial Reactive Oxygen Species

目的研究定向下调心肌CD36的表达对高脂饮食诱导的肥胖小鼠心肌组织中活性氧簇(ROS)含量的影响。方法4周龄的雄性C57小鼠,随机分为正常对照组(N-mock)、肥胖对照组(O-mock)及肥胖干预组(O-CD36),采用高脂饮食诱导肥胖。6周龄时,向心肌内分别注射靶向CD36(O-CD36)或靶向无关基因(N-mock、O-mock)的重组慢病毒。10周后,取小鼠心室组织检测CD36的mRNA及蛋白表达水平;行油红O染色检测心肌组织内中性脂质含量;并使用冷冻切片染色法及流式细胞术检测心肌细胞内ROS含量。结果慢病毒介导的RNA干扰显著下调了O-CD36小鼠心肌组织中CD36的表达。肥胖引起心肌组织内中性脂质蓄积,下调心肌CD36的表达显著减少了中性脂质的含量。高脂饮食还导致心肌ROS的含量显著增加,而下调CD36的表达可以改善甚至逆转这一进程。结论 CD36在高脂肪酸代谢所引起的ROS生成增加中起重要作用,定向下调心肌CD36的表达可以减少心肌组织ROS的含量,改善心肌氧化应激。

Objective To study the effeets of cardiac - specific CD36 inhibition on generation of myoearctial reactive oxygen species （ROS）. Methods Four - week - old male C57 mice were randomized into normal control group （ N - mock） , obese control group （ O - mock） and obese intervention group （O -CD36）. High -fat -diet （HFD） was used to induce obesity in this study. Mice were subjected to intramyocardial injection with recombinant lentiviral vectors carrying short hairpin RNAs targeting murine CD36 （for O -CD36） or ir- relevant gene （for N - mock and O - mock）. Ten weeks later, ventricular tissues were obtained. CD36 mRNA and protein expression were measured by I＇IT- PCR and Western blot. Myocardial neutral lipid content was detected by oil red O staining. Two methods were chosen to measure the ROS production in the myoeardium. Results Lentivirus - mediated RNAi effectively down - regulated CD36 ex- pression in O -CD36 mice heart. HFD induced obesity inereased neutral lipid deposition in the heart, but this process was ameliorated by cardiac CD36 inhibition. HFD feeding induced myocardial ROS overproduction, which was reversed by cardiac - specific CI）36 suppres- sion. Conclusion CD36 plays an important role in myocardial ROS overproduction during fatty acid hypermetabolic states. Targeted cardiae CD36 inhibition improves myocardial ROS generation, and ameliorates myocardial oxidative stess as well.