Polysaccharides form mushroom stimulate macrophages through intestinal epithelial cells

香菇多糖一直被认为是香菇中含有的抗肿瘤多糖，其分子量估计在40万以上。香菇多糖的抗肿瘤活性是通过宿主介导的，不杀伤癌细胞。然而，尚未确定香菇多糖是否在肠道中被吸收。本研究采用肠上皮细胞系caco2细胞（顶端侧）和巨噬细胞细胞系RAW 264.7细胞（底外侧）共培养系统，阐明香菇多糖对巨噬细胞的刺激作用。50 μg/ml香菇多糖处理Caco2细胞（2.5×10^5个细胞/孔），与RAW 264.7细胞（5×10^5个细胞/孔）共培养。仅在基底外侧（150 pg）检测到TNF-α的产生，而在根尖侧未检测到。在相同条件下，在基底外侧添加过氧化氢酶时，TNF-α的产生被抑制50%，而超氧化物歧化酶则没有。香菇多糖直接刺激RAW 264.7细胞不产生TNF-α。此外，在不含RAW 264.7细胞的情况下，用相同浓度的香菇多糖培养caco2细胞时，两者均不产生TNF-α。基底外侧均未检出香菇多糖。这些结果表明，香菇多糖刺激肠上皮细胞产生H_2O_2和新产生的H_2O_2在细胞间串扰中起重要作用，促进巨噬细胞产生TNF-α。

Lentinan has been known as an antitumor polysaccharide contained in Lentinula edodes, and its molecular weight was estimated to be more than 400,000. Lentinan shows the antitumor activity through host-mediated, because it does not kill cancer cells. However, it has not been ascertained whether or not lentinan was absorbed in intestine. In this study, co-culture system using intestinal epithelial cell line, caco2 cells (apical side), and macrophage cell lines, RAW 264.7 cells (basolateral side), was applied to clarify how lentinan stimulated macrophage. Caco2 cells (2.5×10^5 cells/well) were treated with 50 μg/ml lentinan, and then were co-cultured with RAW 264.7 cells (5×10^5 cells/well). TNF-α production was detected just in basolateral side (150 pg), not in apical side. When catalase was added in basolateral side in the same condition, TNF-α production was inhibited to 50%, but superoxide dismutase did not. RAW 264.7 cells stimulated directly with lentinan did not produce TNF-α. Furthermore, when caco2 cells were cultured with lentinan at the same concentration without RAW 264.7 cells, they did not produce TNF-α in both sides. Neither lentinan was detected in basolateral side. These findings suggested that intestinal epithelial cells stimulated with lentinan produced H_2O_2 and newly produced H_2O_2 played an important role in cell to cell cross talking to enhance TNF-α production from macrophages.