Objective:To explore the effects of microRNA-221(miR-221)on inflammation and fibrosis induced by lipopoly-saccharide(LPS)in rat cardiomyocytes and the regulatory role of phosphatidylinositol 3-kinase(PI3K)/seronine/threonine protein kinase(AKT)signaling pathway.Methods:Cultured rat myocardial H9C2 cells in vitro,they were divided into control group(no inter-vention),LPS group(10 μg/ml LPS),experimental group(10 μg/ml LPS+10,20,40,80 μmol/L baicalin),mimics NC group(10 μg/ml LPS+mimics NC transfection),miR-221 mimics group(10 μg/ml LPS+transfection miR-221 mimics),inhibitor NC group(10 μg/ml LPS+transfection inhibitor NC),miR-221 inhibitor group(10 μg/ml LPS+transfection miR-221 inhibitor),10+miR-221 mimics group(10 μg/ml LPS+10 μmol/L baicalin+transfection miR-221 mimics)and 10+miR-221 inhibitor group(10 μg/ml LPS+10 μmol/L baicalin+transfection miR-221 inhibitor)were treated for 24 h.Real-time quantitative fluorescence PCR(RT-qPCR),ELISA,CCK-8,5-acetyne-2'-deoxyuracil nucleoside(EdU)and Transwell chamber methods were used to determine the expression level of miR-221,the expression levels of inflammatory factors,cell viability,cell proliferation and migration ability,Western blot was used to determine the expression levels of EMT-related proteins[E-cadherin,N-cadherin,Vimentin,fibronectin(FN)]and PI3K/AKT pathway related proteins.Results:Cell viability increased in LPS+10 group(P<0.05),so LPS+10 group was selected for follow-up experiment.The results of miR-221 level showed that miR-221 mimics group was higher than mimics NC group(P<0.05),miR-221 inhibitor group was lower than inhibitor NC group(P<0.05).Transfection of miR-221mimics group and miR-221 inhibitor group was successful.Compared with control group,cell proliferation rate and E-cadherin protein level in LPS group were decreased(P<0.05).The expression level of miR-221,cell migration number,IL-6 and TNF-α levels,and the protein levels of p-PI3K,p-AKT,N-cadherin,FN and Vimentin were increased(P<0.05).Compared with LPS group,LPS+10 group significantly reversed the changes of the above indexes(P<0.05).Compared with LPS+10 group,10+miR-221 mimics group reduced the above effect of baicalin in LPS-induced cells(P<0.05).However,miR-221 inhibitor of 10+miR-221 inhibitor group enhanced the above effect of baicalin in LPS-induced cells(P<0.05).Conclusion:Baicalin can inhibit the effects of LPS-induced myocyte H9C2 migration,inflammation and fibrosis and promote their proliferation by down-regulating the expression of miR-221,and its mechanism may be related to the inhibi-tion of PI3K/AKT signaling pathway.

Objective:To explore the effects of microRNA-221(miR-221)on inflammation and fibrosis induced by lipopoly-saccharide(LPS)in rat cardiomyocytes and the regulatory role of phosphatidylinositol 3-kinase(PI3K)/seronine/threonine protein kinase(AKT)signaling pathway.Methods:Cultured rat myocardial H9C2 cells in vitro,they were divided into control group(no inter-vention),LPS group(10 μg/ml LPS),experimental group(10 μg/ml LPS+10,20,40,80 μmol/L baicalin),mimics NC group(10 μg/ml LPS+mimics NC transfection),miR-221 mimics group(10 μg/ml LPS+transfection miR-221 mimics),inhibitor NC group(10 μg/ml LPS+transfection inhibitor NC),miR-221 inhibitor group(10 μg/ml LPS+transfection miR-221 inhibitor),10+miR-221 mimics group(10 μg/ml LPS+10 μmol/L baicalin+transfection miR-221 mimics)and 10+miR-221 inhibitor group(10 μg/ml LPS+10 μmol/L baicalin+transfection miR-221 inhibitor)were treated for 24 h.Real-time quantitative fluorescence PCR(RT-qPCR),ELISA,CCK-8,5-acetyne-2'-deoxyuracil nucleoside(EdU)and Transwell chamber methods were used to determine the expression level of miR-221,the expression levels of inflammatory factors,cell viability,cell proliferation and migration ability,Western blot was used to determine the expression levels of EMT-related proteins[E-cadherin,N-cadherin,Vimentin,fibronectin(FN)]and PI3K/AKT pathway related proteins.Results:Cell viability increased in LPS+10 group(P<0.05),so LPS+10 group was selected for follow-up experiment.The results of miR-221 level showed that miR-221 mimics group was higher than mimics NC group(P<0.05),miR-221 inhibitor group was lower than inhibitor NC group(P<0.05).Transfection of miR-221mimics group and miR-221 inhibitor group was successful.Compared with control group,cell proliferation rate and E-cadherin protein level in LPS group were decreased(P<0.05).The expression level of miR-221,cell migration number,IL-6 and TNF-α levels,and the protein levels of p-PI3K,p-AKT,N-cadherin,FN and Vimentin were increased(P<0.05).Compared with LPS group,LPS+10 group significantly reversed the changes of the above indexes(P<0.05).Compared with LPS+10 group,10+miR-221 mimics group reduced the above effect of baicalin in LPS-induced cells(P<0.05).However,miR-221 inhibitor of 10+miR-221 inhibitor group enhanced the above effect of baicalin in LPS-induced cells(P<0.05).Conclusion:Baicalin can inhibit the effects of LPS-induced myocyte H9C2 migration,inflammation and fibrosis and promote their proliferation by down-regulating the expression of miR-221,and its mechanism may be related to the inhibi-tion of PI3K/AKT signaling pathway.