Polysaccharides form mushroom stimulate macrophages through intestinal epithelial cells

香菇多糖是香菇中的一种抗肿瘤多糖，其分子量估计在40万以上。香菇多糖不杀伤癌细胞，通过宿主介导发挥抗肿瘤作用。然而，香菇多糖在肠道中是否被吸收尚未确定。在这项研究中，共培养系统使用肠上皮细胞系，caco 2细胞（顶侧），和巨噬细胞系，RAW 264.7细胞（底侧），以澄清香菇多糖如何刺激巨噬细胞。用50 μg/ml香菇多糖处理Caco 2细胞（2.5×10^5个细胞/孔），然后与RAW 264.7细胞（5×10^5个细胞/孔）共培养。TNF-α仅在基底侧（150 pg）检测到，而在顶侧未检测到。在相同条件下，在基底侧加入过氧化氢酶，TNF-α的产生被抑制50%，而超氧化物歧化酶则无此作用。香菇多糖直接刺激RAW 264.7细胞不产生TNF-α。caco 2细胞与相同浓度的香菇多糖共同培养，而不与RAW 264.7细胞共同培养时，两侧细胞均不产生TNF-α。基底外侧未见香菇多糖。提示香菇多糖刺激肠上皮细胞产生H_2O_2，新产生的H_2O_2在细胞间交互作用中起重要作用，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.