The alleviative effect of C-phycocyanin peptides against TNBS-induced

Human Diseases and Drug Screening of Shandong Province, Jinan, 250103, China College, Qingdao University, Qingdao, 266000, China ABS T R A C T Introduction: Ulcerative colitis (UC) is an incurable and highly complex chronic inflammatory bowel disease (IBD) affecting millions of people worldwide. C-phycocyanin (C -PC) has been reported to possess outstanding anti- inflammatory activities and can effectively inhibit various inflammation-related diseases. Whether C-PC-derived bioactive peptides can inhibit intestinal inflammation is worth research and consideration. Methods: The inhibition activities of three anti-neuroinflammatory peptides were evaluated using 2-4-6-trinitrobenzen sulfonic acid (TNBS)-induced zebrafish colitis model. Subsequently, the abilities of peptides to promote gastrointestinal motility were also examined. The changes in the intestinal pathological symptoms and ultrastructure of intestinal, reactive oxygen species (ROS) levels, and antioxidant enzymes were then determined after co-treatment with peptides and TNBS. Transcriptome analysis was used to investigate the underlying ameliorating TNBS-induced colitis effects molecular mechanisms of better activity peptide. Furthermore, quantitative reverse -transcription polymerase chain reaction and molecular docking techniques verified the mRNA sequencing results. Results: Three peptides, MHLWAAK, MAQAAEYYR and MDYYFEER, which significantly inhibit macrophage migration, were synthesized. The results showed that these peptides could effectively alleviate the inflammatory responses in the TNBS-induced zebrafish model of colitis. In addition, co-treatment with TNBS and C -PC peptides could decrease ROS production and increase antioxidant enzyme activities in zebrafish larvae. Moreover, MHLWAAK had the most effects on colitis in zebrafish. The