The Immunomodulatory Effects Of Bioactive Peptide QEPV On LPS-induced Inflammation

Dairy-derived bioactive peptides are derived from fermented dairy products which usually mean the short peptides that contain 3-5 amino acids,can't be decomposed by digestive enzymes in gastrointestinal stimulation experiments and easy to absorb.Dairy-derived bioactive peptides usually have biological functions for example being antioxidant and immunomodulatory.The research is concentrated on the function of QEPV which is evaluated both in vitro and in vivo.The results show that QEPV has immunomodulatory effects and reveal the basic biochemistry principles of bioactive function.In vitro experiments show that QEPV can promote the proliferation of RAW264.7 cells with low concentration?0.1g/L?.Compared with control group,RAW264.7 cells pre-cultured with QEPV and then stimulated with LPS,of which the pro-inflammation cytokines expression such as IL-6/IL-12 are significantly reduced and the expression of anti-inflammation cytokine IL-10 is enhanced.Besides,pre-treating RAW264.7 with QEPV can reduce the transcription level of iNOS?COX-2 genes especially the mRNA concentration of iNOS?P<0.05?.In vivo experiments show that when mice are injected with 0.4g/kg weight LPS in abdominal cavity the concentration of IL-6 and NO in serum is significantly increased?P<0.05?.Select 0.4g/kg weight as the concentration of LPS in mice inflammation model.Pre-feeding mice with QEPV and then injecting LPS in abdominal cavity,the concentration of INF-?in serum is significantly reduced and the concentration of IL-12 is higher at 2h but significantly reduced and lower at 4h compared with control group?P<0.05?.On the other hand,the pre-feeding mice have lower concentration of NO/PGE₂ in serum compared with control group.Combined with the results of in vitro experiments,it may be speculated that QEPV regulates the transcription level of iNOS?COX-2 genes which result in the reduction of expression of protein and the enzyme production NO/PGE_2.Both the in vitro and in vivo experiments show that QEPV has immunomodulatory function.The long-time take-in may have good immunomodulatory effects on body.However,the principle of that function needs further research.