Effects of Salvia miltiorrhiza Polysaccharides on Lipopolysaccharide-Induced Inflammatory Factor Release in RAW264.7 Cells

This study investigated the anti-inflammatory effects and possible underlying mechanisms of Salvia miltiorrhiza polysaccharides (SMP) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The cytotoxicity of SMP was detected by the MTT method. The morphological change of RAW264.7 was observed by Diff-Quik staining. Enzyme-linked immunosorbent assay was used to evaluate the production of cytokines in LPS-induced RAW264.7 cells. The nitric oxide (NO) kit assay detected the NO release from LPS-induced RAW264.7 cells. Real-time polymerase chain reaction was used to detect the transcriptions of tumor necrosis factor-alpha (TNF-), interleukin-6 (IL-6), inducible NO synthase (iNOS), and cyclooxygenase (COX)-2 in LPS-induced RAW264.7 cells. The protein expression of nuclear NF-B was measured by Western blot. The results showed that the safe medication range of SMP was less than 3mg/mL. Compared with the LPS model group, SMP (2, 1, and 0.5mg/mL) improved the degree of cell deformation and reduced the amount of pseudopodia, and statistically reduced the secretions of cytokines in cells induced by LPS (P<0.01) at different time points. SMP significantly inhibited the mRNA transcriptions of TNF-, IL-6, iNOS, and COX-2 and the protein expressions of NF-B, p-p65, and p-IBa. In conclusion, this study preliminarily proved the protective effect of SMP on LPS-induced RAW264.7 macrophage. Its mechanism might be related to inhibition of NF-B signal pathway and the gene expressions and secretion of cytokines.