Preparation And Immunomodulatory Study Of Active Peptides From Mytilus Coruscus

Thick-shelled mussels(Mytilus coruscus)are abundant in Zhoushan,Zhejiang.The meat is rich in protein,which is a high-quality protein source for preparing active peptides.In this study,thick-shell mussel meat was used as raw material,and thick-shell mussel immunologically active peptides were first prepared by enzymatic hydrolysis.Using mouse macrophage RAW 264.7 proliferation rate as an evaluation index,the enzymatic preparation of thick-shell mussel immunologically active peptides was optimized.Process,the enzymatic hydrolysate obtained under the optimal process conditions is separated by ultrafiltration,and the most active intercepted component is screened out,named as Mytilus coruscus peptides(MCP),to explore the MCP in cells and animals The research results are as follows:(1)The best enzyme species for preparing active crude peptide of Mytilus coruscus by enzymolysis was trypsin.The single factor experiment was used to optimize the hydrolysis conditions as follows: temperature 37°C,6 h,p H 8,enzyme concentration 2000 U/g,and solid to liquid ratio 1:12(g/m L).The proliferation rate of RAW 264.7 cells was 46.63% in the validation process.Among the five components separated by the ultrafiltration enzymatic hydrolysis polypeptide,the relative proliferation rate of MCP to RAW 264.7 cells was the highest,50.12%.(2)MCP has no toxic effect on RAW 264.7 cells in the range of 12.5-800 ?g/m L.It can promote cell proliferation and activate cells in the range of 12.5-100 ?g/m L,significantly enhance the phagocytosis of macrophages,and increase nitric oxide,reactive oxygen species and cytokine TNF-?,IFN-?,IL-6,IL-1? secretion levels.Western blotting results show that the immune regulation mechanism of MCP is realized through the NF-?B/MAPK signal pathway.(3)MCP improves the body weight and immune organ index of immunosuppressed mice induced by cyclophosphamide,activates the state of splenic lymphocytes,and promotes the phagocytosis of neutral red by peritoneal macrophages and improves delayedtype hypersensitivity.In addition,MCP can also regulate the level of serum hemolysin,the balance of Th1/Th2 cytokine secretion and the secretion of immunoglobulin(Ig)G,Ig A,Ig M,and regulate the immune function of immunosuppressed mice by improving the activity of natural killer cells.The results of this study show that MCP has excellent immunomodulatory activity in vitro and in vivo,which provides a theoretical basis for the high-value utilization of mussel and the development and research of food-borne immunomodulatory peptides.