The Effect Of Lactobacillus Plantarum 12 On The Colitis Induced By Dextran Sulfate Sodium Salt In Mice

Ulcerative colitis(UC)is a common inflammatory bowel disease,which can cause weight loss,diarrhea,fever and other symptoms of the host,chronic inflammation of the colon may develop into colon cancer.Lactic acid bacteria have been widely studied due to its good probiotics,and many related reports have shown that lactic acid bacteria have good therapeutic effects on colon inflammation.In this paper,four lactobacillus strains stored in the key laboratory of probiotics functional characteristics research in Dalian were used as raw materials,we studied the tolerance,safety and effect of the strain on colitis induced by DSS in mice,it's aimed to screen out one lactobacillus strain that can treat colon inflammation and provide a new direction for the treatment of colitis.The functional characteristics of four strains of Lactobacillus(L.plantarum 4,L.plantarum 12,L.plantarum 14,L.plantarum 37)were determined.The survival rates of L.plantarum 4 and L.plantarum 12 were 98.97% and 95.50%,respectively,in simulated gastric juice(pH = 2.5)for 3 h,and 79.18% and 84.14%,respectively,in simulated intestinal juice for 8 h.The adhesion index of L.plantarum 12 was 18.02±5.2 CFU/cell,significantly higher than that of L.plantarum 4,and then,L.plantarum 12 was selected for follow-up experiments.L.plantarum 12 has a certain tolerance to bile salts due to its ability to produce bile brine lyase.Subsequently,the safety of L.plantarum 12 was evaluated,and the results showed that it did not produce biogenic amines harmful to human body and did not have hemolysis.Therefore,L.plantarum 12 is a safe strain with good functional characteristics and can be used in subsequent in vivo experiments.Next,the colitis mouse model was induced by DSS,and the effect of L.plantarum 12 on the colitis mouse model was further studied.By observing the general situation of colitis mice,it can be preliminarily judged that L.plantarum 12 group can alleviate the symptoms of weight loss and colon shortening in colitis mice.And the colon tissue sections of mice showed that L.plantarum 12 could alleviate the disappearance of crypt and goblet cells induced by DSS.ELISA assay of the expression of inflammatory cytokines in serum showed that the L.plantarum 12 significantly reduced the expression of proinflammatory cytokines IL-8 and TNF-?,and increased the expression of anti-inflammatory cytokines IL-10 compared with the model group.Finally,an analysis of the intestinal flora colitis in the mice faeces was determined,the results showed that L.plantarum 12 could improve the DSS induced ulcerative colitis mice intestinal flora diversity,promote the growth of beneficial bacteria,effectively inhibit the growth of intestinal pathogenic bacteria,and relieve colitis mice intestinal dysbacteriosis,promote the recovery of intestinal flora,reducing intestinal inflammation response;Preliminary analysis of colonic proteomics in colitis mice showed that L.plantarum 12 could inhibit the production of proinflammatory proteins such as Tnfaip8 and Bax,stimulate the production of intestinal mucosal proteins such as MUC2 and stress proteins such as HSP70,so as to alleviate the inflammatory response in colitis mice.In summary,L.plantarum 12 could alleviate ulcerative colitis in mice,and is a safe strain.Therefore,L.plantarum 12 has the potential to become a probiotic strain capable of treating inflammatory diseases of the colon.