| The Cyclina sinensis occupies an important position in the aquaculture of shellfish in China.It is not only rich in a variety of amino acids,but also has a high value of food and medicinal purposes.Recent studies have shown that the polysaccharides and peptides extracted from the C.sinensis exhibited good biological activities,such as immunomodulation,antioxidant,anti-tumour and so on.In our laboratory,we found that SCSP had a significant repairing effect on immune system damage,but little research has been reported its immunomodulatory mechanisms and its hepatorenal protection.Therefore,in this study,RAW264.7 cells were used as an in vitro cell model to explore the immune regulation mechanism of SCSP on RAW264.7 cells.CTX was used to induce mouse models of hypoimmunity and liver and kidney damage to explore the in vivo immune regulation of SCSP and its repairing effects on liver and kidney damage,and provide experimental basis for the rational application of SCSP.Results: 1.Study on the immunoregulatory mechanism of SCSP on RAW264.7cells After treated with SCSP,the protein levels of the NF-κB pathway to the RAW264.7cells were significantly increased,except for IκBα which the protein levels was significantly decreased.Moreover,the phosphorylation levels of PI3 K and Akt protein were significantly increased in the PI3K/Akt pathway,and p38,Erk and JNK protein phosphorylation in the MAPK pathway was significantly activated.After pretreatment with NF-κB inhibitor,PI3 K inhibitor and MAPK inhibitor,SCSP induced an increase in the protein concentrations of p-Akt and p-Erk and a decrease in the protein concentrations of IκBα.2.Study on the immunoregulatory mechanism of SCSP on immunosuppressed mice SCSP could restore the body weight loss of the immunosuppressed mice,and increase the indices of spleen and thymus.After treated with SCSP,the serum levels of cytokines(IL-1β,IL-6 and TNF-α)were significantly increased,the proliferative capacity and phagocytosis of mouse peritoneal macrophages as well as the proliferation capacity of splenic lymphocytes in vitro was also significantly increased when compared with the modle group.In addition,the results of western blot showed the same trend of protein changes in the spleen as in the RAW264.7 cells in vitro.Moreover,the immunohistochemical results showed that the expression of NF-κB p65,p-PI3 K and p-p38 in the spleen were significantly increased when compared with the modle group.3.Protective effects of SCSP against CTX-induced hepatotoxicity The results indicated that SCSP could significantly attenuate the CTX-induced hepatotoxicity by decreasing the levels of ALT,AST,TG and MDA,and increase the activities of SOD,GSH-Px and CAT.In addition,the levels of IL-1β,IL-6 and TNF-α in liver tissue were significantly reduced.Moreover,the protein levels of IKKα,IKKβ,NF-κB p50,TLR4 were down-regulated,and the protein levels IκBα were up-regulated after treated with SCSP.The protein levels of Bax,Caspase-3 and Caspase-9 were also down-regulated,and the protein level of Bcl-2 was up-regulated after treated with SCSP.4.Protective effects of SCSP against CTX-induced nephrotoxicity The results indicated that the kidney injury index and cytokine levels were restored after treated with SCSP.In addition,the activities of SOD,GSH-Px and CAT were increased,while the MDA content was significantly decreased after treated with SCSP.Moreover,SCSP could significantly inhibit the inflammatory factors by down-regulating the protein levels of NF-κB p50,NF-κB p65,IKKα,IKKβ,and up-regulating the protein levels of IκBα.SCSP could also inhibit apoptosis by up-regulating the protein levels of Bcl-2,and down-regulating the protein levels of Bax,Caspase-3 and Caspase-9 in the kidney tissues.In conclusion,this study found that SCSP not only regulates the body’s immune function,but also has a repair effect on the hepatorenal toxicity caused by CTX,which provides an experimental basis for the further development and utilization of SCSP. |
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