ABSTRACT
Background:
Polysaccharides from edible mushrooms possess immunomodulatory, anti-inflammatory, and anti-tumor activities. Recent studies indicated that necroptosis plays a role in the pathogenesis of inflammatory diseases and mediates increased expression of inflammatory cytokines.
Objective:
Therefore, it is imperative to determine the impact of polysaccharide extract from Lentinula edodes (L. edodes) on inflammatory cytokines in experimental model of colitis in mice.
Methods:
Female C57BL/6 mice divided into three or four mice per group were used for this study. Polysaccharide sample was orally administered to mice prior to (7 days) and during colitis induction with 2.5% dextran sodium sulfate (7 days), followed by additional 3 days of administration. Changes in body weight and colon length were used as markers for colitis, and pro-inflammatory cytokines and tumor necrosis factor receptor 1 (TNFR1) expressions, as well as necroptosis were analyzed in the colon of colitis mice. Data obtained were analysed by Tukey-Kramer and two-tailed standard t tests.
Results:
The results indicated that the polysaccharide sample suppressed colitis in mice using effects on the body weight and colon length as markers. Also, it was demonstrated that necrostatin-1, a specific inhibitor of necroptosis, suppressed the expression of interleukin (IL)-8, a pro-inflammatory chemokine, in Caco-2 cells induced necroptosis induced by zVAD and TNF-α, an indication that necroptosis may be involved in the expression of pro-inflammatory cytokines. Moreover, the polysaccharide sample suppressed the expression of pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, IL-6, IL-1β, and interferon (IFN)-γ in the colon of mice.
Conclusion:
These results suggested that the suppressive effects of the polysaccharide sample on inflammatory cytokines expression may contribute to its anti-colitis effect, and so may serve as a potent therapeutic agent against inflammatory bowel disease.
Keywords:
Edible mushrooms; polysaccharides; necroptosis; colitis; pro-inflammatory cytokines
Thumbnail
Thumbnail
Thumbnail
Thumbnail
Crude polysaccharides (LeA: 500 µg/mouse) was administered to mice prior to colitis induction (with 2.5% DSS (w/v) in drinking water) for 7 days and during colitis induction for another 7 days, followed by additional 3 days of administration. Crude polysaccharide sample from a different strain of L. edodes (500 µg/mouse) that possessed anti-inflammatory activity was used as positive control. (A) Body weight of colitis mice treated with LeA. (B and C) Colon length of colitis mice treated with LeA. Crude polysaccharides sample was separated using DEAE-sepharose CL-6B column chromatography and NaCl solution of increasing ionic strength (0.0, 0.5, and 1.0 M) was used to elute the column. (D) Elution profile of LeA showing two peaks, fractions LeAP1 (eluted with 0.0 M NaCl) and LeAP2 (eluted with 0.5 M NaCl). Values are expressed as Mean ± SD (n=5). **P<0.01.
Colitis was induced in mice with 2.5% DSS (w/v) in drinking water for 7 days. Polysaccharide sample (300 µg/mouse) was orally administered to mice prior to (7 days) and during colitis induction (7 days), followed by additional 3 days of administration. (A) Body weight of mice treated with polysaccharide sample. (B and C) Colon length of mice treated with polysaccharide sample. The dose of LeAP1 administered was determined from the percentage yield after chromatographic separation and lyophilization (LeAP1: 59.5% of 500 µg = 297.5 ≈ 300 µg) to represent the equivalence of 500 µg/mouse crude polysaccharides previously administered. Values are expressed as mean ± SD (n=4-5). **P<0.01.
