MiR-146a通过炎症参与小鼠糖尿病心肌病的机制研究

Mechanism of miR-146a Involved in Diabetic Cardiomyopathy in Mice Through Inflammation

目的:探讨microRNA-146a (miR-146a)对小鼠糖尿病心肌病炎症的影响。方法:20只雄性C57BL/6小鼠随机分为对照组和糖尿病心肌模型组,模型组利用链脲佐菌素(STZ,50 mg/kg)腹腔注射建立糖尿病心肌病模型,对照组给予等体积枸橼酸钠缓冲液,建模成功后提取心脏组织RNA,利用qRT-PCR检测心肌组织中miR-146a和炎症因子白介素1β(IL-1β),白介素6(IL-6),单核趋化因子1(MCP-1)以及NF-κB/p65的mRNA表达;依次分离原代心肌细胞,成纤维细胞和内皮细胞,给予高糖处理后,检测细胞中miR-146a,IL-1β,IL-6,MCP-1以及NF-κB/p65的mRNA表达;内皮细胞转染miR-146a mimic或miR-146a inhibitor,观察炎症因子的表达情况。结果:糖尿病心肌病心肌组织中miR-146a水平较对照组降低(P<0.05),炎症因子IL-1β,IL-6,MCP-1以及NF-κB/p65的mRNA表达高于对照组(P<0.05);与对照组相比,高糖分别处理原代心肌细胞和成纤维细胞后miR-146a表达未改变(P>0.05),而高糖降低内皮细胞中miR-146a的表达(P<0.05);高糖增加内皮细胞炎症因子IL-1β,IL-6,MCP-1及NF-κB/p65的mRNA水平(P<0.05);内皮细胞转染miR-146a mimic后可阻止由于高糖所导致的内皮细胞中IL-1β,IL-6,MCP-1及NF-κB/p65的增加(P<0.05),而转染miR-146a inhibitor后,可引起正常对照组细胞中炎症因子IL-1β,IL-6,MCP-1以及NF-κB/p65表达的增加(P<0.05)。结论:糖尿病心肌病中miR-146a的降低以及炎症的增加,与内皮细胞受损相关,且可能通过miR-146a影响炎症因子的表达。

Objective: To investigate the effect of microRNA-146a(miR-146a) on inflammation of diabetic cardiomyopathy in mice. Methods: Twenty male C57BL/6 mice were randomly divided into control group and diabetic myocardial model group, with 10 rats in each group. The model group was established by intraperitoneal injection of streptozotocin(STZ, 50 mg/kg) to establish a diabetic cardiomyopathy model. The control group was intraperitoneally injected with an equal volume of sodium citrate buffer. Cardiac tissue RNA was extracted. qRT-PCR was used to detect the mRNA expression of miR-146a and inflammatory factor interleukin-1β(IL-1β),interleukin-6(IL-6), monocyte chemotactic factor 1(MCP-1) and NF-κB/p65;then cardiomyocytes, fibroblasts and endothelial cells were sequentially isolated from mice, and treated with high glucose. The mRNA expressions of miR-146a, IL-1β, IL-6, MCP-1 and NF-κB/p65 were detected in the cells. The expression of inflammatory factors was observed by transfecting miR-146a mimic or miR-146a inhibitor into endothelial cells. Results: The level of miR-146a in myocardial tissue of diabetic cardiomyopathy was lower than that of the control group(P<0.05), and the mRNA expression of inflammatory factors IL-1β, IL-6, MCP-1 and NF-κB/p65 was higher than that of the control group(P<0.05). After treatment of cardiomyocytes and fibroblasts with high glucose, the expression of miR-146a was unchanged compared with the control group(P>0.05), while high glucose decreased the expression of miR-146a in endothelial cells(P <0.05). High glucose increased mRNA levels of endothelial cytokines IL-1β, IL-6, MCP-1 and NF-κB/p65(P <0.05). Then transfected with miR-146a mimic prevented high glucose induced the increase of IL-1β, IL-6, MCP-1 and NF-κB/p65 in endothelial cells(P <0.05), and transfection of miR-146a inhibitor can cause inflammatory factor IL-1β, IL-6, MCP-1 and NF-κB/p65 expression increased in normal control cells(P <0.05). Conclusion: The decrease of miR-146a and the increase of inflammation in diabetic cardiomyopathy are associated with endothelial cell damage, and these effects may be affect the expression of inflammatory factors through miR-146a.