干扰CD36的表达对高脂饮食诱导的肥胖小鼠心肌细胞钙调控的影响

摘要

Objective To study the effects of cardiospecific CD36 suppression on myocardial calcium handling in high-fat-diet (HFD) induced obese mice.Methods Four weeks aged male C57 mice were randomized into normal control group (N-mock),obese control group (O-mock) and obese intervention group (O-CD36).HFD was used to induce obesity in this research.At six weeks of age,mice were subjected to intramyocardial injection with recombinant lentivirus targeting murine CD36 (for O-CD36) or irrelevant gene (for N-mock and O-mock) to down-regulate their expressions.When mice reached 16 weeks of age,left ventricular tissues were obtained.The mRNA and protein expressions of CD36 and sarco/endoplasmic reticulum Ca2 +-ATPase 2a (SERCA2a) were detected by RT-PCR and Western blot.Isolated ventricular myocytes were obtained by enzymatic dissociation method,and used for myocardial calcium transient detection via live cell station.Results The mRNA and protein levels of myocardial CD36 were not influenced by HFD feeding.Lentivirus-mediated RNAi significantly down-regulated cardiac CD36 expression.Obesity decreased myocardial SERCA2a expression,reduced calcium transient velocity,and damaged calcium handling as well.Cardiospecific CD36 inhibition ameliorated the myocardial SERCA2a deficiency.Meanwhile,the calcium mishandling was improved.Conclusion Cardiospecific CD36 suppression ameliorated myocardial calcium mishandling associated with HFD induced obesity.%目的 研究干扰心肌组织中脂肪酸转位酶CD36的表达对高脂饮食诱导的肥胖小鼠心肌细胞钙调控的影响.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,经心肌注射靶向CD36(O-CD36)或靶向无关基因(N-mock、O-mock)的重组慢病毒,以下调心肌组织中目标基因的表达.16周龄时,取小鼠左心室组织,检测CD36和肌质网钙泵(SERCA2a)的mRNA和蛋白表达;并分离单个心室肌细胞,使用活细胞工作站检测心肌细胞钙瞬变.结果 肥胖小鼠心肌组织中CD36的表达较正常小鼠无显著改变,慢病毒介导的RNA干扰显著下调了CD36的表达.肥胖引起心肌细胞SERCA2a的蛋白表达降低及肌质网钙处理能力的下降;下调CD36的表达增加了SERCA2a的含量,并改善了钙调控异常.结论 下调心肌组织中CD36的表达可改善肥胖所引起的心肌细胞钙调控异常.