circFAT1调节miR-211-5p/CCND2轴对糖尿病心肌病大鼠心肌损伤的影响

circFAT1 affects myocardial injury in rats with diabetic cardiomyopathy by regulating the miR-211-5p/CCND2 axis

目的探讨circFAT1对糖尿病心肌病(DCM)大鼠心肌损伤的影响及对miR-211-5p/细胞周期蛋白D2(CCND2)轴的调节机制。方法利用高糖高脂饲料联合链脲佐菌素建立DCM大鼠模型,并随机分为DCM组、circ-NC组、circFAT1组、circFAT1+激动剂-NC组和circFAT1+miR-211-5p激动剂组,以喂食普通饲料的大鼠作为对照组,每组20只。实时PCR检测心肌组织中circFAT1、miR-211-5p、CCND2水平;Western blotting检测心肌组织CCND2蛋白表达;生化分析仪检测大鼠空腹血糖(FBG)、总胆固醇(TC)和甘油三酯(TG)水平;心脏超声检测大鼠心功能;HE和Masson染色观察心肌组织病理形态;TUNEL染色检测心肌细胞凋亡情况;ELISA法检测白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)水平;双荧光素酶报告基因实验验证circFAT1、miR-211-5p、CCND2之间的靶向关系。结果与对照组相比,DCM组circFAT1、CCND2 mRNA及蛋白表达,左心室射血分数(LVEF)、左心室缩短分数(LVFS)水平降低(P<0.05),FBG、TC、TG、左心室舒张末期直径(LVEDd)、左心室收缩末期直径(LVEDs)、胶原容积分数(CVF)、细胞凋亡率、IL-1β、IL-6、TNF-α水平均升高(P<0.05);与DCM组相比,circFAT1组circFAT1、CCND2 mRNA及蛋白表达,LVEF、LVFS水平升高(P<0.05),FBG、TC、TG、LVEDd、LVEDs、CVF、细胞凋亡率、IL-1β、IL-6、TNF-α水平降低(P<0.05);miR-211-5p激动剂逆转了circFAT1对DCM心肌损伤的缓解作用,且CCND2 mRNA及蛋白表达降低(P<0.05)。结论circFAT1通过调控miR-211-5p/CCND2轴减轻DCM大鼠心肌组织损伤。

Objective To explore the effect of circFAT1 on myocardial injury in rats with diabetic cardiomyopathy(DCM)and the regulatory mechanism of circFAT1 on the miR-211-5p/CCND2 axis.Methods A DCM rat model was established by injecting rats with high glucose and high fat feed combined with STZ.The rats were randomly separated into DCM,circ-NC,circFAT1,circFAT1+agomir-NC,and circFAT1+miR-211-5p agomir groups,with 20 rats in each group;rats fed regular feed were used as control.Real-time PCR was used to detect the levels of circFAT1,miR-211-5p,and CCND2 in myocardial tissue and Western blotting was used to detect CCND2 expression in myocardial tissue.The levels of fasting blood glucose(FBG),total cholesterol(TC),and triglycerides(TG)of rats were recorded.Cardiac ultrasound was used to detect the cardiac function of rats.Furthermore,HE and Masson staining were used to observe the pathological morphology of myocardial tissue and TUNEL staining was used to detect myocardial apoptosis.Additionally,ELISA was used to detect the levels of interleukin-1β(IL-1β),IL-6,and tumor necrosis factor-α(TNF-α).Double luciferase reporter gene assay was used to verify the targeting relationship among circFAT1,miR-211-5p,and CCND2.Results Compared with the control group,the expression of circFAT1 and CCND2 mRNA and protein and the levels of LVEF and LVFS decreased in the DCM group(P<0.05)whereas,the levels of FBG,TC,TG,LVEDd,LVEDs,CVF,cell apoptosis rate,IL-1β,IL-6,and TNF-αincreased(P<0.05).Compared with the DCM group,the levels of circFAT1,CCND2 mRNA and protein,LVEF,and LVFS increased in the circFAT1 group(P<0.05),whereas the levels of FBG,TC,TG,LVEDd,LVEDs,CVF,cell apoptosis rate,IL-1β,IL-6,and TNF-αdecreased(P<0.05).Furthermore,miR-211-5p agomir reversed the protective effect of circFAT1 on DCM myocardial injury,and the expression of CCND2 mRNA and protein decreased(P<0.05).Conclu-sion circFAT1 alleviates myocardial tissue damage in rats with DCM by regulating the miR-211-5p/CCND2 axis.