Inhibitory Effect of Cranberry Extract on LPS Induced Inflammatory Response in RAW246.7 Cells
To study the anti-inflammatory effect of cranberry extract on inflammation suppression induced by lipopolysaccharide, and explore its mechanism. Cell inflammatory model was established with RAW264.7 cells treated with lipopolysaccharide. Cell viability of RAW264.7 cells treated with cranberry extract were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The effect of cranberry extract on nucleus was observed by 4',6-diamidino-2-phenylindole(DAPI)staining. The activity of nitric oxide synthase (NOS) was determined by fluorescence analysis. Enzyme-linked immunosorbent assay (ELISA) for determination of IL-1 beta , IL-6 and TNF- alpha . RAW264.7 cells were treated with cranberry extract for 24 h, and the expression of Keap1, Nrf2, HO-1, IKK alpha / beta and NF- kappa Bp65 were detected by Western blotting. The result showed that the inflammatory model was established by 5 micro g/mL lipopolysaccharide, the highest level of inflammation was reached at 24 hours. There was no significant toxic effect on RAW246.7 cells in the range of 5 micro g/mL-400 micro g/mL, and the cell nucleus was intact and without obvious damage. Compared with the model group, cranberry extract could significantly inhibit the activity of NOS and decreased the content of IL-1 beta , IL-6, TNF- alpha with the increase of dose. The Western blot result showed that cranberry extract inhibited the expression of Keap1, IKK alpha / beta , NF- kappa Bp65 and increase the expression of Nrf2 and HO-1 protein levels. These results suggest that cranberry extract can inhibit the inflammatory response induced by lipopolysaccharide, and its mechanism may be related to activation of Keap1/Nrf2/HO-1 signaling pathway and NF- kappa Bp65.