长链非编码RNA Kcnq1ot1对小鼠糖尿病心肌病的作用

Role of long non-coding RNA Kcnq1ot1 in mice with diabetic cardiomyopathy

目的研究长链非编码RNA Kcnq1ot1在糖尿病心肌病中的作用及机制。方法C57BL/6小鼠分为对照组和糖尿病(DM)组,注射链脲佐菌素建立DM模型后喂养8周建立糖尿病心肌病模型。DM组小鼠注射慢病毒干扰Kcnq1ot1表达。qRT-PCR检测小鼠左心室Kcnq1ot1表达。超声心动图、HE和Masson染色评价小鼠左心室结构和功能,Western blot检测collagenⅠ、Ⅲ和TGF-β1/Smads通路表达水平。免疫组化、qRT-PCR和Western blot检测左心室NLRP3、caspase-1、IL-1β和GSDMD-N表达。结果与对照组相比,Kcnq1ot1在DM小鼠左心室中明显升高,注射Kcnq1ot1-shRNA慢病毒后被抑制。DM组小鼠心脏收缩和舒张功能明显下降,出现心肌细胞肥大及纤维化;干扰Kcnq1ot1后DM小鼠心脏功能和结构明显改善。此外,干扰Kcnq1ot1后胶原表达下调,TGF-β1/Smads通路被抑制,焦亡相关分子表达下调。结论LncRNA Kcnq1ot1在糖尿病心肌病小鼠中表达升高,干扰Kcnq1ot1能够通过抑制心肌焦亡,抑制TGF-β1/Smads通路,减轻糖尿病心肌间质纤维化,改善心脏结构和功能。

Aim To investigate the role of long non-coding RNA Kcnq1ot1 in mice with diabetic cardiomyopathy(DCM)and its mechanism.Methods C57BL/6 mice were divided into control group and diabetic group(DM).DM model was established by intraperitoneal injection of streptozocin.The DCM model was established by feeding for eight weeks.Kcnq1ot1-shRNA lentivirus was injected to inhibit Kcnq1ot1.The expression levels of Kcnq1ot1 in the left ventricle of mice in each group were detected by qRT-PCR.The function and structure of the left ventricular were evaluated using echocardiography,HE and Masson staining.The expression levels of collagenⅠ,collagenⅢand TGF-β1/Smads signaling pathway were detected by Western blot.The expression levels of NLRP3,caspase-1,IL-1βand GSDMD-N in the left ventricular tissue of mice were detected by immunohistochemistry,qRT-PCR and Western blot.Results qRT-PCR showed that the expression of Kcnq1ot1 in the left ventricular tissues of diabetic mice significantly increased compared with the control group,and was significantly inhibited by Kcnq1ot1-shRNA.The systolic and diastolic functions of diabetic hearts significantly decreased,and cardiomyocyte hypertrophy and myocardial fibrosis appeared as well.The cardiac function and structure of the diabetic mice were significantly improved,collagen expression levels were down-regulated and the TGF-β1/Smads pathways were inhibited after silencing Kcnq1ot1.The expression levels of the pyroptosis related factors were down-regulated in the DM+Kcnq1ot1-shRNA group.Conclusions The expression levels of lncRNA Kcnq1ot1 increase in the STZ-induced diabetic mice.Silencing Kcnq1ot1 can alleviate the pyroptosis and inhibit the TGF-β1/Smads pathway,thus ameliorating myocardial fibrosis.