The Role And Mechanism Of MicroRNA-15a In Heart Failure

Objective: This study verified the role and molecular mechanism of microRNA-15 a in heart failure through in vivo and in vitro experiments.Methods:(1)In vivo experiment,male SPF SD(Sprague Dawley)rats aged 8 weeks were random Ly divided into sham operation group,model group,microRNA-15 a group and microRNA-15 a control group(microRNA-15 a blank vector control group).The rat model of heart failure was established by abdominal aortic coarctation.In sham operation group,the abdominal aorta was not ligated.Echocardiography and micro-PET/CT were performed 8weeks after surgery,and different drugs were injected in groups after successful modeling was confirmed.Rats in sham operation group and model group were injected with 0.25 m L normal saline via tail vein,rats in microRNA-15 a group were injected with 0.25 m L diluted microRNA-15 a via tail vein,and rats in microRNA-15 a control group were injected with0.25 m L diluted microRNA-15 a blank vector via tail vein.Two weeks after administration,echocardiography and micro-PET/CT were performed again.After the detection,the rats were sacrificed and the heart was removed to separate the left ventricle.H&E staining,Masson staining,Trim72 protein immunohistochemical staining,RT-q PCR and Western blot were performed.(2)In vitro experiments,rat cardiac fibroblast(RCF)lines were cultured and transfected with microRNA-15 a simulators and inhibitors.Proliferation and migration of transfected cardiac fibroblasts were detected by CCK-8 and Transwell experiments.The expression levels of microRNA-15 a and Trim72 proteins were detected by RT-q PCR and Western blot.Results:(1)In vivo experiment: 2 weeks after injection of microRNA-15 a loaded with AAV virus,ultrasound results showed that the heart function of rats in microRNA-15 a group was significantly improved compared with that in model group(P<0.05).Micro-pet /CT results showed that myocardial filling defect in microRNA-15 a group was significantly improved compared with that in model group.H&E staining results showed that the structural disorder of myocardial fibers in microRNA-15 a group was significantly reduced compared with that in model group.Masson staining showed that collagen fiber content in myocardial tissue of rats in microRNA-15 a group was significantly decreased compared with that in model group(P<0.01).Immunohistochemistry showed that the expression of Trim72 protein in myocardial tissue of rats in microRNA-15 a group was significantly down-regulated compared with that in model group(P<0.01).Rt-qpcr results showed that the expression level of microRNA-15 a in microRNA-15 a group was significantly up-regulated compared with the model group(P<0.01),and the m RNA expression level of Trim72 protein was significantly down-regulated compared with the model group(P<0.01).Western blot analysis showed that the expression level of Trim72 protein in myocardial tissue of microRNA-15 a group was significantly down-regulated compared with that of model group(P<0.01).(2)In vitro experiment: after transfection with microRNA-15 a mimic,inhibitor and corresponding control,CCK8 results showed that the number of myocardial fibroblasts in mimic group was significantly decreased compared with blank group(P<0.05);Transwell results showed that the number of migrated cells in mimic group was significantly reduced compared with NC mimic group(P<0.01).Compared with the inhibitor NC group,the number of migrated cells was significantly increased(P<0.01);Rt-qpcr results showed that:Compared with NC mimic group,microRNA-15 a expression level was significantly up-regulated(P<0.01),and Trim72 m RNA expression level was significantly down-regulated(P<0.01).Compared with inhibitor NC group,microRNA-15 a expression level was significantly down-regulated(P<0.01),and Trim72 protein m RNA expression level was significantly up-regulated(P<0.01).Western blot showed that the expression of Trim72 protein in mimic group was significantly down-regulated compared with NC mimic group(P<0.05).Compared with inhibitor NC group,Trim72 protein expression was significantly up-regulated(P<0.05).Conclusions:(1)MicroRNA-15 a can effectively improve cardiac function in rats with heart failure.(2)MicroRNA-15 a inhibits proliferation and migration of myocardial fibroblasts by negatively regulating the expression of Trim72 protein.