Study On The Prevention And Treatment Of Chitooligosaccharide On Animal Experimental Inflammatory Bowel Disease

As one of the three major diseases in the pig industry,porcine inflammatory bowel disease(IBD)can be induced by various factors,which the main manifestation is the damage of the intestinal mucosal barrier.While the farms mostly rely on antibiotics to prevent and control IBD,the trend of "Ban and restrict the usage of antibiotics" is emerging.It is of great significance to develop a kind of natural substances-"antibiotics replacement",with anti-inflammatory and mucosal repair effects.Chitooligosaccharide(COS)not only has the functions of anti-inflammatory and mucosal repaired,but also is a natural product that has large yield and easy to be obtained,which has great potential to be developed as a functional feed additive for the prevention and treatment of inflammatory bowel disease.At present,there are few studies on the effects of COS on intestinal inflammation in pigs.In view of this,the study evaluated the improvement of COS on lipopolysaccharides(LPS)-induced intestinal epithelial inflammation in intestinal epithelial cells and observed the melioration on Dextran sulfate sodium salt(DSS)-induced colitis in mice,which lays the foundation for the further development and utilization of COS,and also provides a theoretical basis for the comprehensive prevention and control of inflammatory bowel disease.Methods:(1)CCK8 kit was used to determine the effect of COS on the proliferation rate of LPS-induced intestinal epithelial cells;TEER and FITC-dextran were used to evaluate the effect of COS on the permeability of monolayer fusion epithelium;(2)Western blot was used to detect the effect of COS on the expression of tight junction proteins ZO-1,Occludin,Claudin-1,Claudin-4 and Mitogen-activated protein kinases(MAPK)signaling pathway key proteins ERK,JNK,P38 in LPS-induced intestinal epithelial cells;(3)DSS-induced mouse enteritis model was constructed to observe the improvement of COS on mouse colitis.The study found that:(1)Under the stimulation of LPS,the proliferation rate of intestinal epithelial cells decreased significantly,and COS pretreatment can significantly inhibit the decrease induced by LPS(p<0.01).COS can increase the transepithelial electrical resistance(TEER)of the monolayer fusion intestinal epithelium,and significantly improve the effect of LPS-induced cells that the reduce in TEER and the increase in the permeability of FITC-dextran(p<0.01).COS can significantly inhibit the up-regulation of TNF-α and IL-β in intestinal epithelial cells induced by LPS(p<0.01).(2)After exposure to LPS,tight junction proteins are significantly down-regulated,while COS pretreatment can significantly improve down-regulation of LPS-induced tight junction proteins ZO-1,Occludin,Claudin-1and Claudin-4;COS can down-regulate the high expression of LPS-induced ERK.(3)The mouse in the DSS group showed weight loss,depression,dry color,slow response,appetite loss with anal bleeding;Anatomical observation and analysis showed thymus and spleen smaller and the liver became larger;Pathological anatomy and histological observation showed that colonic hemorrhage,shortening,thinning of muscle layer,shortening of intestinal villi and decreasing number of goblet cells;Blood analysis shows that the number of peripheral white blood cells rise,the number of lymphocytes lessen and the expression of inflammatory factors TNF-α and IL-βincrease;Western blot detection shows that tight junction proteins ZO-1,Occludin,Claudin-1,Claudin-4 and MAPK signaling pathway key proteins ERK,JNK and P38 were significantly down-regulated in the colon of DSS-treated mice.The inflammatory response of mice in the COS treatment group was significantly reduced.Meanwhile,the tight junction proteins ZO-1,Occludin,Claudin-1,Claudin-4 and the key proteins of the MAPK signaling pathway ERK,JNK and P38 were significantly up-regulated compared with the DSS treatment group.The results showed that:(1)Chitooligosaccharides have obvious anti-inflammatory and mucosal protective functions;(2)Chitooligosaccharides have obvious protective effects on inflammatory bowel disease;(3)The protective effects of Chitooligosaccharides on inflammatory bowel disease is related to the up-regulation of tight junction proteins expression;(4)Chitooligosaccharides regulates the expression of tight junction proteins through the MAPK signaling pathway to improve inflammatory bowel disease.