Abstract
To investigate the effect of salidroside (Sal) on the inflammatory activation of lipopolysaccharide (LPS)-induced murine macrophage cell line J774.1 and its possible mechanism, the cells were treated with PBS, LPS (0.5 µg/mL) or different doses of Sal (5, 25, 125 µg/mL) + LPS (0.5 µg/mL). CCK-8 colorimetric method was used to detect the cell activity. The enzyme-linked immunosorbent assay (ELISA) was used to detect the contents of TNF-α, MCP-1 and MIP-2 in the supernatant, and the content of NO in the supernatant was determined by nitrate reductase method. The expression levels of iNOS mRNA was detected by RT-PCR. Western blot was used to detect the expression levels of iNOS protein in cytoplasm and NF-kappaB/p65 (NF-κB/p65) protein in both cytoplasm and nucleus, and DNA binding activity of NF-κB/p65 was detected by using TransAMTM NF-κB/p65 activity assay kit. The results showed that the treatment with 0.5 µg/mL LPS and different doses of Sal (5, 25, 125 µg/mL) for 12 h had no effect on cell viability. Compared with LPS stimulation group, pretreatment with Sal significantly reduced the contents of TNF-α, MCP-1, MIP-2 and NO in culture supernatant induced by LPS in a dose dependent manner (P < 0.05), downregulated the expression levels of iNOS mRNA and protein (P < 0.05), decreased the expression level of NF-κB/p65 protein in nucleus (P < 0.05) while accordingly increased that in cytoplasm (P < 0.05), and decreased DNA binding activity of NF-κB/p65 in a dose dependent manner (P < 0.05). The results suggested that Sal pretreatment can reduce macrophage inflammatory activation induced by LPS, and the mechanism may be through the LPS/TLR4/NF-κB signaling pathway, thereby reducing the excessive expression and secretion of inflammatory mediators and cytokines.
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