a1 Institute of Biochemistry, Food Science and Nutrition, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot 76100, Israel
a2 Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Rehovot 76100, Israel
Polysaccharides are one of the most potent mushroom-derived substances exhibiting anti-inflammatory and immunomodulatory properties. The aims of the present study were to determine whether orally administered glucans from the edible mushroom Pleurotus pulmonarius could attenuate or prevent the development of experimental colitis in mice. Colonic inflammation was induced in mice by treatment with 3·5 % dextran sulfate sodium (DSS) for 18 d. Before or after DSS administration, mice were given hot water solubles (HWS) or mycelium extract (ME) (2 or 20 mg per mouse) daily in their food. Colonic damage was macroscopically and histologically evaluated. Inflammation was assessed by changes in colon length, TNF-α levels released by colonic samples in organ culture and myeloperoxidase (MPO) activity. mRNA levels of pro-inflammatory (IL-1β) and anti-inflammatory (IL-10) cytokines in colonic samples were determined by quantitative real-time RT-PCR. P. pulmonarius glucans attenuated and prevented the development of symptoms associated with DSS-induced colitis. High doses of HWS and ME blocked colon shortening, suppressed MPO activity and improved macroscopic score in all treatment groups. In addition, histological damage from colitis was reduced by HWS and ME at all doses. The tissue levels of TNF-α protein were significantly decreased and correlated with degree of inflammation and macroscopic score. All treatments significantly attenuated the increased DSS-mediated expression levels of IL-1β. We conclude that the different glucan preparations (HWS or ME) harvested from P. pulmonarius when orally administered to DSS-treated mice attenuate the development of colonic inflammation, suggesting putative clinical utility for these extracts in the treatment of colitis.
(Received November 10 2008)
(Revised July 02 2009)
(Accepted July 06 2009)
(Online publication September 22 2009)
Abbreviations: DSS, dextran sulfate sodium; HWS, hot water solubles; ME, mycelium extract; MPO, myeloperoxidase; ppm, parts per million