The Study Of Sagittaria Sagittifolia Polysaccharide About Its Regulating Immune Function On Mice And Its Possible Mechanism On MTOR Signaling Pathway

Objective The regulating immune function and anti-tumor activity of Sagittaria sagittifolia polysaccharide were observed in S180 tumour-bearing mice and low immune mice. The regulating immune function of Sagittaria sagittifolia polysaccharide about macrophage and its possible mechanism on the m TOR signaling pathway were observed in Raw264.7 cells.Methods(1) The study on immunosuppressed mice:50 ICR male mice were randomly divided into five groups by weight : normal group, model group and different polysaccharide dose groups(100、200、300 mg/kg?d).The Sagittaria sagittifolia polysaccharide was administrated intragastrically to each dose group by gavage in 28 days. Normal control group and model were fed with distilled water. On the 21 st day, the normal control group was injected with normal saline, the other 4 groups of mice wasinjected with hydrocortisone 25 mg/kg?d for 6 days. The weight change and organ index were observed in the study. The phagocytic index of macrophages was observed in the carbon clearance test and fluorescent microsphere experiment. The study on S180 tumor bearing mice : 56 ICR male mice were randomly divided into seven groups by weight : normal group, model group, different Sagittaria sagittifolia polysaccharide dose groups(100、200、300 mg/kg?d), cyclophosphamide group(20 mg/kg?d) and lentinan group(0.577 mg/kg, twice a week). From the first day to the eleventh day, the sagittaria polysaccharide was administrated intragastrically to different polysaccharide dose groups by gavage. The rest of groups were fed with distilled water. On the twelfth day, the mice of all groups except the normal group were made to be the S180 tumor bearing mice. Sagittaria sagittifolia polysaccharide was administrated intragastrically to all groups by gavage for 11 days.On the 23 th day, the organ index, the tumor inhibiting rate and the concentrations of serum IL-2、TNF-α、SOD、MDA were measured in this study.(2)The secretion effect of cytokine IL-2、TNF-α and NO of different dose Sagittaria sagittifolia polysaccharide(5、50、500 μg/m L) and lentinan(100 μg/m L) on Raw264.7 were investigated by ELISA and Griess method. The expression of m TOR/PTEN m RNA and protein were measured by RT-PCR and Western Blot. Results(1) The study on immunosuppressed mice: the organ index of Sagittaria sagittifolia polysaccharide groups were significantly higher than the model group(P<0.05). The macrophage phagocytic index of polysaccharide groups in the carbon clearance test and fluorescent microsphere experiment were higher than the model group(P<0.05).The study on S180 tumor bearing mice : The spleen index of the Sagittaria sagittifolia polysaccharide middle and high dose group were significantly higher than the model group(P<0.05). The concentration of serum IL-2,TNF-α of the Sagittaria sagittifolia polysaccharide all dose groups were significantly higher than the model group(P < 0.05). The tumor weight of the Sagittaria sagittifolia polysaccharide high dose group was significantly lower than the model group and its tumor inhibiting rate was 0.648(P<0.05). The concentrations of serum SOD and MDA of the Sagittaria sagittifolia polysaccharide high dose group was significantly higher than the model group(P<0.05).(2) The study on Raw264.7 cells:The concentration of serum IL-2,TNF-α of the Sagittaria sagittifolia polysaccharide all dose groups were significantly higher than the normal group(P<0.05). The concentration of serum NO of the Sagittaria sagittifolia polysaccharide high dose group were significantly higher than the normal group(P<0.05).In the RT-PCR experiment,the expression of Mtor m RNA of the Sagittaria sagittifolia polysaccharide middle,high dose group were significantly lower than the normal group and down-regulated(inferior to 0.578 and 0.391 fold)(P<0.05). In the Western Blot experiment,the expression of MTOR protein of the Sagittaria sagittifolia polysaccharide high dose group were significantly lower than the normal group(P<0.05). The expression of PTEN gene had no statistical significance in all groups(P>0.05). Conclusions(1)Sagittaria sagittifolia polysaccharide can enhance macrophage phagocytic ability of mice to reinforce the nonspecific immunity in a certain extent.Sagittaria sagittifolia polysaccharide can regulate immune function of mice and increase the anti-tumor and antioxidant effect.(2) Sagittaria sagittifolia polysaccharide could enhance the secretion effect of cytokine IL-2, TNF-α and NO. Its mechanism may be associated with the m TOR signaling pathway and make the way to be inhibited.The polysaccharide didn’t have the relationship with PI3K/AKT/PTEN/m TOR pathway, it may have the relationship with the other m TOR signaling pathway.