慈菇多糖通过mTOR信号通路提高巨噬细胞功能

目的 探讨哺乳动物雷帕霉素靶蛋白（mTOR）信号通路在慈菇多糖提高RAW 264.7巨噬细胞功能中的作用。方法 体外培养RAW 264.7巨噬细胞，分别用ELISA和Griess法检测不同剂量慈菇多糖（5、50、500 μg/mL）和香菇多糖（100 μg/mL）对巨噬细胞分泌白介素2（IL-2）、肿瘤坏死因子α（TNF-α）、一氧化氮（NO）的影响；用RT-PCR和Western blot检测各组巨噬细胞mTOR/第10染色体缺失与张力蛋白同源的磷酸酶基因（PTEN）mRNA和蛋白表达变化。结果 与对照组比较，慈菇多糖低、中、高剂量组，香菇多糖组巨噬细胞内IL-2含量[分别为（68.216±1.609）、（70.850±6.669）、（89.634±8.399）、（84.367±8.165）pg/mL]上升；慈菇多糖中、高剂量组，香菇多糖组巨噬细胞内TNF-α含量[分别为（46.989±7.895）、（70.739±7.452）、（48.125±6.757）pg/mL]上升，慈菇多糖高剂量组巨噬细胞内NO值[为（7.199±1.242）μmol/L]上升，差异均有统计学意义（均P<0.01）；慈菇多糖中、高剂量组RAW 264.7细胞mTOR mRNA表达低于对照组（P<0.05）；慈菇多糖高剂量组、香菇多糖组mTOR蛋白表达低于对照组（P<0.05）。结论 慈菇多糖可能通过mTOR相关信号通路提高巨噬细胞功能。

Enhancement effect of Sagittaria sagittifolia polysaccharide on immune function of macrophages through mTOR signal pathway

Objective To study the role of mammalian target of rapamycin (mTOR) signaling pathway in enhancement effect of Sagittaria sagittifolia polysaccharide on immune function of macrophage with Raw 264.7 cells.Methods RAW 264.7 cells were incubated with Dulbecco's modified Eagle's medium (DMEM) in vitro.The effects of different dose Sagittaria sagittifolia polysaccharide (5,50,and 500 μg/mL) and lentinan (100 μg/mL) on interleukin-2 (IL-2),tumor necrosis factor α (TNF-α),and nitric oxide (NO) secretions of Raw 264.7 cells were determined with enzyme-linked immunosorbent assay (ELISA) and Griess method.The expressions of mTOR/phosphatase and tensin homologdeleted on chromosome ten (PTEN) mRNA and protein were measured with real time PCR (RT-PCR) and Western blot.Results The IL-2 level was 68.216±1.609,70.850±6.669,89.634±8.399,84.367±8.165 pg/ml in low,moderate,and high dose Sagittaria sagittifolia polysaccharide group and lentinan group;the TNF-α level was 46.989±7.895,70.739±7.452,and 48.125±6.757 pg/ml in moderage and high dose Sagittaria sagittifolia polysaccharide group and lentinan group;the NO level was 7.199±1.242 μmol/L in high dose Sagittaria sagittifolia polysaccharide group;and all the levels were significantly higher compared to those of the model group (IL-2:50.661±5.006 pg/ml,TNF-α:23.788±4.093 pg/ml,NO:2.950±0.723 μmol/L)(all P<0.01).The expressions of mTOR mRNA in RAW 264.7 cells cultured with moderate and high dose Sagittaria sagittifolia polysaccharide were significantly lower than that of the negative control group (P=0.021,P=0.003).The expressions of mTOR protein in RAW 264.7 cells cultured with high dose Sagittaria sagittifolia polysaccharide and lentinan declined significantly compared to that of the negative control group (P=0.003,P=0.049).Conclusion Sagittaria sagittifolia polysaccharide could enhance the activity of phagocytosis of macrophages through mTOR signal pathway.