Astragalus mongholicus polysaccharide inhibits lipopolysaccharide-induced production of TNF-α and interleukin-8

AIM: To explore the effect of Astragalus mongholicus polysaccharide (APS) on gene expression and mitogen-activated protein kinase (MAPK) transcriptional activity in intestinal epithelial cells (IEC). METHODS: IEC were divided into control group, lipopolysaccharide (LPS) group, LPS+ 50 mu g/mL APS group, LPS+ 100 mu g/ml APS group, LPS+ 200 mu g/mL APS group, and LPS+ 500 mu g/mL APS group. Levels of mRNAs in LPS-induced inflammatory factors, tumor necrosis factor (TNF)-alpha and interleukin (IL)-8, were measured by reverse transcription-polymerase chain reaction. MAPK protein level was measured by Western blotting. RESULTS: The levels of TNF-alpha and IL-8 mRNAs were significantly higher in IEC with LPS-induced damage than in control cells. APS significantly abrogated the LPS-induced expression of the TNF-alpha and IL-8 genes. APS did not block the activation of extracellular signal-regulated kinase or c Jun amino-terminal kinase, but inhibited the activation of p38, suggesting that APS inhibits LPS-induced production of TNF-alpha and IL-8 mRNAs, possibly by suppressing the p38 signaling pathway. CONCLUSION: APS-modulated bacterial product-mediated p38 signaling represents an attractive strategy for prevention and treatment of intestinal inflammation. (C) 2009 The WIG Press and Baishideng. All rights reserved.