Study on the mechanism of inhibiting ragweed pollen and LPS-induced inflammation in RAW264.7 cells by Petroleum ether extract of Trametes suaveolens

Western blot to detect iNOS, COX-2, p-p65, p-IκBα, NLRP3, ASC, Caspase-1 protein expression levels in cells; The expressions of IL-6, TNF-α, IL-6, IL-18 and IL-1β in cells were detected by qRT-PCR. The expression of NLRP3 in cells was detected by immunofluorescence technique.Results The fraction of petroleum ether extract of Trametes suaveolens (BFT) obtained by silica gel column chromatography accounted for 56.81% of the total content.

There were no toxic effects of BFT on RAW264.7 macrophages. Compared with the control group, co-stimulation with RWE (10 μg/mL) and LPS (100 ng/mL) significantly decreased cell viability (P<0.01), but after pretreatment with BFT, cell viability was significantly increased (P<0.01), and the levels of inflammatory factors and ROS were significantly decreased (P<0.01) in RAW264.7 cells. Compared with the model group, BFT significantly reduced the phosphorylation levels of p65, IκBα, and the protein expression levels of iNOS, COX-2, NLRP3, Caspase-1 and ASC were significantly reduced in RAW264.7 macrophages (P<0.01) The qRT-PCR results showed that BFT significantly down-regulated the expression of IL-6, TNF-α, IL-6, IL-18, and IL-1β in cells; Compared with the model group, NLRP3 fluorescence intensity was attenuated in RAW264.7 macrophages after treatment with BFT.Conclusion BFT inhibits RAW264.7 macrophage inflammation induced by RWE and LPS through the ROS/NF-κB/NLRP3 signalling pathway.