Study On The Regulation And Mechanism Of Burdock Inulin On Intestinal Immunity In Mice

The recognition and rapid response of the intestine to its contacts depends on the protective function of the intestinal immune system.Intestinal immune system dysfunction causes ulcerative colitis,lipid enteritis,intestinal lymphangiectasis,hypogammaglobulinemia,and nonalcoholic fatty liver,dermatitis,obesity,type ?diabetes,atherosclerosis and so on.Intestinal immune system dysfunction is also closely related to the occurrence of malnutrition and cancer.For the treatment of immunocompromised patients,immunotherapy has attracted more and more attention.For the regulation of intestinal immunity,chemical drugs,biological drugs,traditional Chinese medicine and probiotics are mainly used for prevention and treatment.As an important active ingredient of Chinese medicine,plant polysaccharides have been widely studied for their safety and non-toxicity.Burdock inulin(BFO)is a low molecular weight inulin extracted from the root of burdock,with a molecular weight of 2000-5000 Da.D-2 fructose,which is configured by furan,is connected by ?(2?1)glycosidic bonds,and the terminal is pyridine.Glucopyranose is linked to fructose by a-(1? 2)glycosidic bonds.Burdock has been found to have a variety of biological activities such as antioxidant,anti-allergic,immunomodulatory or immune stimulating and anti-inflammatory activities in previous studies.It was also found that BFO is not digested by the upper digestive tract and has the characteristics of prebiotics,but its effect on the role of intestinal immunity has not been studied.In this study,the effects of BFO on the growth performance and intestinal microorganisms of normal mice were studied in a normal mouse model,and the effect of BFO on colitis mice was studied in a mouse model of ulcerative colitis,thereby explaining the effect of BFO on intestinal immunity regulationThe study found that in normal mouse models,oral administration of BFO at concentrations of 100 mg/kg/day,250 mg/kg/day and 500 mg/kg/day for 8 weeks showed that BFO had no significant effect on the body weight of mice,but could promote the body length and tail length of the mice and increase the thymus index of the mice and had no obvious effect on the spleen index.The concentrations of ALT,AST,UA,UR,and CR in the serum were measured by biochemical detection methods,and the results showed that the levels were not obvious changes indicate that BFO has no toxic side effects on the liver and kidneys at this stage.The kit was used to measure the content of MDA and H2O2,and the enzyme activity of SOD and GSH-Px.The results showed that BFO can reduce the content of MDA and H2O2 and increase SOD and the level of GSH-Px can improve the antioxidant performance of mice.The measurement of mouse intestinal index shows that BFO can increase the small intestine,cecum,colorectum and total intestine index of mice.Pyrosequencing was used to detect the composition of the small intestine,cecum,colorectum,and feces at 500 mg/kg/day.The results showed that BFO treatment can greatly change the composition and structure of the small intestine,cecum,colon,and feces,and reduce the diversity and abundance of microbial biota in the small intestine and colorectum,increasing the diversity of the microbial flora in the cecum and reducing its abundance,has no significant effect on the diversity and richness of the microbial flora in the feces.At the phylum level,for the fecal microbiota,Firmicutes(F)and Bacteroidetes(B)are the dominant species.Compared with the control group,Bacteroidetes increased significantly,while Firmicutes decreased significantly,and the F/B ratio decreased.Studies have shown that F/B can prevent obesity in mice.The dominant microflora in the BFO-treated group in the small intestine was Firmicutes.Compared with the blank group,the abundance of Proteobacteria in the BFO group decreased significantly,and the proportion of Firmicutes increased significantly.For the cecum microbiota and colorectal microbiota,the dominant species were Firmicutes(F)and Bacteroidetes(B)(>96%).Compared with the blank group,the F/B ratio in the BFO group increased,and Verrucomicrobia increased significantly.Verrucomicrobia is involved in mucin degradation and plays an important role in intestinal integrity.At the genus level,the relative abundances of most genus in the feces in the blank group were Lactobacillus,Acinetobacter,Rheinheimera,Gemella,Alistipes,Paracoccus,and Blauti,which were higher than those in the BFO group.Alloprevotella,Bacteroides and Helicobacte were lower than the BFO group.In the small intestine,the relative abundance of Lactobacillus in the BFO group was significantly higher than that in the blank group.In addition,Lactobacillus of the cecum and colorectal flora in the BFO group also increased.Lactobacillus is an important genus of probiotics and has been shown to have anti-obesity,anti-inflammatory and anti-tumor health effects.This indicates that BFO plays different roles in different parts of the intestine.However,the specific mechanism of BFO in the small intestine,cecum and colorectum needs further research.In a mouse model of colitis,measurement of body weight,DAI index,colorectal length,and spleen index,the result showed that BFO can restore DSS-induced weight loss in mice,increase DAI index,colon length,and spleen swelling.Using a kit to measure the levels of SOD,GSH-PX,H2O2,and MDA in mouse serum showed that the levels of MDA and H2O2 in the serum of the model group increased,while the levels of SOD and GSH-PX decreased,which indicates that antioxidant performance of mice in the model group decreased.In different concentrations of the BFO group,compared with the model group,the contents of MDA and H2O2 were reduced,and the contents of SOD and GSH-PX were increased.The results show that BFO can improve the decline of antioxidant properties caused by ulcerative colitis.By measuring the MPO activity,the results showed that the activity of MPO in the model group increased significantly,while MPO activity in the BFO group decreased.The results of H&E staining showed that the colonic epithelium of the mice in the blank group was intact and there was no ulcerative colitis erosion.The model group had severe inflammatory lesions in the colon tissue,and the mice in the BFO group had significantly reduced colon inflammation.The TNF-? content was measured by ELISA.The results showed that the TNF-? content in the serum of the model group mice increased significantly,and different concentrations of BFO could down-regulate the TNF-? content to varying degrees.The expression of inflammatory cytokine mRNA was determined by qPCR.The results showed that the expression of inflammatory cytokine mRNA in the blank group was very low,the expression of inflammatory cytokine mRNA in the DSS group was significantly increased.The mRNA expression levels(IL-6,IL-1?,TNF-?,iNOS,and COX-2)were significantly reduced,which indicates that BFO can inhibit the expression of inflammatory cytokines to reduce DSS-induced colitis.In summary,BFO can improve the growth performance and antioxidant performance of normal mice,improve the intestinal microbial composition of mice,increase beneficial bacteria,reduce harmful bacteria,reduce the expression of inflammatory factor mRNA in colitis tissue,and improve antioxidant properties of the inflammation mice to prevent and treat the occurrence of colitis.