Preliminary Study On The Effects Of Lactobacillus On DSS-induced Colitis In Mice

Inflammatory bowel disease(IBD)is a chronic nonspecific inflammatory disease that occur in the gastrointestinal tract caused by a variety of factors.At present,the treatment of IBD is mainly about balancing the intestinal microbial community,protecting the intestinal epithelial barrier and regulating intestinal mucosal immunity.In recent years,there have been many studies to improve the symptoms of IBD by supplementing probiotics.This study will conduct a preliminary study on the mechanism of improving IBD by Lactobacillus,which preserved in our laboratory.The Lactobacillus selected in this study was Lactobacillus plantarum CGMCC 6326,and the colitis mice model induced by 2.5%DSS solution was established.By observing the indicators such as body weight and colon tissue morphology,the ability of this strain of Lactobacillus to improve experimental colitis was preliminarily judged.The effects of Lactobacillus plantarum 6326 on intestinal immunity in colitis mice were evaluated by measuring the levels of cytokines TFN-?,IL-6,IL-1?,IL-10 and TGF-? in colon tissue of each group.The total antioxidant capacity,malondialdehyde level,superoxide dismutase activity and glutathione peroxidase activity were measured in the serum of mice to determine whether the Lactobacillus strain could improve inflammation caused by oxidative stress.In addition,we collected mouse feces and used 16S rRNA high-throughput sequencing technology to detect intestinal microbes in the feces of each group of mice,and analyzed the regulation of Lactobacillus plantarum 6326 on DSS-induced intestinal flora imbalance.By intragastric administration of Lactobacillus plantarum 6326,the mice recovered to a low body weight of 18.77±0.93 g,the disease activity index was as low as 2.27+0.57,the morphology of colon tissue was improved,and the histopathological score was 3.50+0.42.it was preliminarily determined that Lactobacillus plantarum 6326 had the ability to improve colitis.The relative transcription levels of inflammatory cytokines TFN-?,IL-6 and IL-1? in colon tissues of mice were decreased as follows:1.22+0.84,15.48+11.69,2.52+2.05;the relative transcription levels of anti-inflammatory cytokines IL-10 and TGF-?were increased to 5.52+1.26 and 2.74+1.56.From the perspective of immune indexes,Lactobacillus plantarum 6326 can regulate the balance of immune factors relative to the transcription level.The serum MDA content was reduced to 6.40+1.13 mmol/mL,GSH-PX activity was 1271.43+195.29 U/mL,and SOD activity was 100.46+1.33 U/mL.In terms of antioxidant indexes,Lactobacillus plantarum 6326 has antioxidant capacity in vivo and protects cells from oxidative damage.According to the intestinal flora indicators,Lactobacillus plantarum 6326 restored the diversity and abundance of intestinal flora,reduced the harmful bacteria in the intestinal tract associated with inflammation,such asPeptostreptococcaceae and Clostridiaceae,increased the beneficial bacteria in the intestinal tract,such as Lactobacillus and Ruminococcus,and improved the intestinal microecological environment.In summary,the Lactobacillus plantarum CGMCC 6326 isolated and preserved in the laboratory,has the potential to prevent IBD and lay the foundation for chronic intestinal diseases.