Zhikang Capsule Ameliorates Inflammation, Drives Polarization to M2 Macrophages, and Inhibits Apoptosis in Lipopolysaccharide-induced RAW264.7 Cells

Objective:To explore the anti-inflammatory effect of the traditional Chinese medicine Zhikang capsule(ZKC)on lipopolysaccharide(LPS)-induced RAW264.7 cells.Methods:Safe concentrations of ZKC(0.175,0.35,and 0.7 mg/mL)were used after the half-maximal inhibitory concentration(IC_(50))of RAW264.7 cells was calculated through the CCK-8 assay.In addition,the optimal intervention duration of ZKC(0.7 mg/mL)on RAW264.7 cells was determined to be 6 h,since all proinflammatory mediators[tumor necrosis factor-alpha(TNF-α),interleukin-1 beta(IL-1β),inteleukin-6(IL-6),cyclooxygenase-2(COX-2),inducible nitric oxide synthase(iNOS),and monocyte chemotactic protein-1(MCP-1)]had a decreasing tendency and relatively down-regulated mRNA expression levels as compared with other durations(4,8,and 12 h).RAW264.7 cells were pretreated with ZKC at various concentrations(0.175,0.35 and 0.7 mg/mL)for 6 h and then stimulated with LPS(1 μg/mL)for an additional 12 h.Results:In terms of inflammation,ZKC could reverse LPS-induced upregulation of TNF-α,IL-1β,IL-6,COX-2,iNOS,and MCP-1 at both the mRNA and protein levels in RAW264.7 cells in a dose-dependent manner.In terms of the NF-κB signaling pathway,ZKC could reduce phosphorylated p65 and promote M2 polarization of RAW264.7 cells under LPS stimulation in a dose-dependent manner.Moreover,ZKC exhibited a protective effect on macrophages from apoptosis.Conclusion:ZKC exhibited obvious anti­inflammatory and anti-apoptotic effects on LPS-induced RAW264.7 cells at the cellular level,and a weakened NF-κB signaling pathway may be a potential significant target.