Objective To investigate the effect of isoorientin(ISO)on lipopolysaccharide(LPS)-induced myocardial cell damage through regulation of the high-mobility group protein B1(HMGB1)receptor for the advanced glycation end-product(RAGE)signaling pathway.Methods H9c2 myocardial cells were incubated with LPS,and the cells were randomly assigned to an LPS induction group(Model group,1 μg/mL LPS),a low concentration ISO intervention group(ISO-L group,50 μmol/L ISO),a high concentration ISO interven-tion group(ISO-H group,100 μmol/L ISO),or a high concentration ISO+RAGE activator late glycation end-products(AGES)group(ISO-H+AGES group,100 μmol/L ISO+10 μg/mL AGES),with an additional control group(Control group).A cell counting kit 8 assay was used to determine the viability of the H9c2 cells.Flow cytometry was used to determine the rate of apoptosis of the H9c2 cells.An ELISA kit was used to determine the levels of oxidative stress-related factors,superoxide dismutase(SOD),malondialdehyde(MDA),and glutathione peroxidase(GSH-Px)in the H9c2 cells.ELISA method was also used to determine the levels of inflammatory factors,interleukin-1β(IL-1 β),tumor necrosis factor α(TNF-α),and lactate dehydrogenase(LDH)in the H9c2 cells.Western blotting was used to determine the expression levels of the HMGB1-RAGE signaling pathway and apoptosis-related proteins in the H9c2 cells.Results Compared with the Control group,the expression levels of optical density(OD)at 450 nm(48 h and 72 h),SOD,GSH-Px,and B-cell lymphoma-2(Bcl-2)proteins in the H9c2 cells in the Model group were significantly reduced(P＜0.05),and the apoptosis rate,MDA,IL-1β,TNF-α,and LDH levels,and the expression levels of HMGB1,RAGE,Bcl-2 associated X protein(Bax),and cleaved caspase-3 proteins were significantly increased(P＜0.05).Compared with the Model group,the expression levels of OD450(48 h and 72 h),SOD,GSH-Px,and Bcl-2 proteins in the H9c2 cells in the ISO-L and ISO-H groups were significantly increased(P＜0.05),and the apoptosis rate,MDA,IL-1β,TNF-α,and LDH levels,and the expression levels of HMGB1,RAGE,Bax,and cleaved caspase-3 proteins were significantly decreased(P＜0.05).AGES weakened the alleviating effect of ISO on LPS-induced H9c2 cell damage.Conclusion ISO alleviates LPS-induced myocardial cell damage by inhibiting excessive activation of the HMGB-RAGE signaling pathway.

Objective To investigate the effect of isoorientin(ISO)on lipopolysaccharide(LPS)-induced myocardial cell damage through regulation of the high-mobility group protein B1(HMGB1)receptor for the advanced glycation end-product(RAGE)signaling pathway.Methods H9c2 myocardial cells were incubated with LPS,and the cells were randomly assigned to an LPS induction group(Model group,1 μg/mL LPS),a low concentration ISO intervention group(ISO-L group,50 μmol/L ISO),a high concentration ISO interven-tion group(ISO-H group,100 μmol/L ISO),or a high concentration ISO+RAGE activator late glycation end-products(AGES)group(ISO-H+AGES group,100 μmol/L ISO+10 μg/mL AGES),with an additional control group(Control group).A cell counting kit 8 assay was used to determine the viability of the H9c2 cells.Flow cytometry was used to determine the rate of apoptosis of the H9c2 cells.An ELISA kit was used to determine the levels of oxidative stress-related factors,superoxide dismutase(SOD),malondialdehyde(MDA),and glutathione peroxidase(GSH-Px)in the H9c2 cells.ELISA method was also used to determine the levels of inflammatory factors,interleukin-1β(IL-1 β),tumor necrosis factor α(TNF-α),and lactate dehydrogenase(LDH)in the H9c2 cells.Western blotting was used to determine the expression levels of the HMGB1-RAGE signaling pathway and apoptosis-related proteins in the H9c2 cells.Results Compared with the Control group,the expression levels of optical density(OD)at 450 nm(48 h and 72 h),SOD,GSH-Px,and B-cell lymphoma-2(Bcl-2)proteins in the H9c2 cells in the Model group were significantly reduced(P＜0.05),and the apoptosis rate,MDA,IL-1β,TNF-α,and LDH levels,and the expression levels of HMGB1,RAGE,Bcl-2 associated X protein(Bax),and cleaved caspase-3 proteins were significantly increased(P＜0.05).Compared with the Model group,the expression levels of OD450(48 h and 72 h),SOD,GSH-Px,and Bcl-2 proteins in the H9c2 cells in the ISO-L and ISO-H groups were significantly increased(P＜0.05),and the apoptosis rate,MDA,IL-1β,TNF-α,and LDH levels,and the expression levels of HMGB1,RAGE,Bax,and cleaved caspase-3 proteins were significantly decreased(P＜0.05).AGES weakened the alleviating effect of ISO on LPS-induced H9c2 cell damage.Conclusion ISO alleviates LPS-induced myocardial cell damage by inhibiting excessive activation of the HMGB-RAGE signaling pathway.