Abstract
Astragalus polysaccharide (APS) has been widely reported to play an important role in inflammatory response. In this study, we aimed to explore the effects and underlying mechanisms of APS on lipopolysaccharide (LPS)-induced inflammation injury in H9c2 cardiomyoblasts. H9c2 cells were treated with different concentrations of APS, and cell viability was detected by the Cell Counting Kit-8 (CCK-8) assay. Then, the effect of APS on cell viability and apoptosis induced by LPS was determined by CCK-8, flow cytometry, and western blot. The expression and release of inflammatory cytokines were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and enzyme-linked immunosorbent assay (ELISA). Furthermore, expression of miR-127 in H9c2 cells was analyzed by qRT-PCR, and knocked down by transfection with miR-127 inhibitor. Western blot was used to analyze signaling pathway molecules. APS had no effect on H9c2 cells viability. However, APS could alleviate LPS-induced inflammation injury by increasing cell viability, reducing apoptosis, and inhibiting release of inflammatory cytokines in H9c2 cells ( P < 0.05). Additionally, we found that APS increased toll-like receptor 4 (TLR4) expressions in LPS-treated H9c2 cells. Mechanistically, we found that APS exerted the protective effect by down-regulating LPS-increased expression of miR-127 ( P < 0.05), inhibiting nuclear factor kappa B (NF-κB), JNK and promoting phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways in LPS-treated H9c2 cells. The results demonstrated that APS could protect H9c2 cells against LPS-induced inflammation injury, which might be partially due to miR-127 down-regulation and regulation of NF-κB, JNK, and PI3K/AKT signaling pathways. These findings indicated that APS might be a potential therapeutic drug for treatment of myocarditis.