The Preparation Of Pea Starch-lauric Acid Complex And Its Effect On Mice With Acute Colitis

BackgroundWith the alteration of lifestyle and dietary habits,the incidence of inflammatory bowel disease(IBD)has been rapidly increasing.IBD is often a chronic and recurrent condition with a low fatality rate,yet there is no effective cure available.It is essential to design preventive strategies for IBD and formulate dietary plans that minimize drug utilization.The starch-lipid complex is a type of resistant starch(RS),and plays a crucial role in promoting intestinal health,but there are few studies on the effects of RS on IBD.In this study,pea starch and lauric acid were selected as raw materials to prepare the pea starch-lauric acid complex(RS5),and its effect on mice-induced acute colitis by dextran sulfate sodium(DSS)was observed and evaluated.MethodsRS5 was prepared from pea starch and lauric acid by an enzyme-damp-heat treatment method.After RS5 was prepared,the content of RS was detected by in vitro simulation.The complex index of pea starch and lauric acid was analyzed by the damp-heat and iodine complexation.The gelatinization properties of RS5 were evaluated using rapid viscosity analyzer.The morphological of RS5 was examined via scanning electron microscopy.The crystal structure of RS5 was analyzed using X-ray diffraction.The thermal characteristics of RS5 were investigated through differential scanning calorimetry.Thirty 7-week-old male C57/BL6J mice were fed adaptive for one week,and then randomly divided into three groups,control(sterile water,10 mL/kg body weight normal saline administration),DSS(3%DSS water,10 mL/kg body weight normal saline administration),and DSS_RS5(3%DSS water,3.25 g/kg body weight RS5 administration).Body weight,disease activity index(DAI)score,and so on were recorded every day.After 7 days,mice were euthanized after anesthesia and samples of serum,spleen,colon,and colon contents were collected.Hematoxylin-eosin staining was employed to observe the pathological lesion of the colon,followed by a histological score.Immunohistochemistry was utilized to examine tight junction proteins and mucin in the colon.The concentrations of serum inflammatory cytokines were quantified using enzyme-linked immunosorbent assay.Real-time quantitative polymerase chain reaction was employed to evaluate the mRNA expression levels of inflammatory cytokines and tight junction in the colon.Western blot analysis was employed to assess the expression of tight junction proteins and proteins related to the NF-κB signaling pathway.16S rRNA was used to analyze the changes in microbiota.Spearman’s rank correlation analysis was employed to examine the association between microbiota and acute colitis-related indicators.ResultsThe content of RS was 15%in pea starch and 32.44%in RS5,and the compound yield of pea starch and lauric acid was stable.The surface of RS5 is rough,the structure is densely arranged,the crystal structure is a typical V type,the gelatinization temperature is increased,and the stability is well.Compared with the DSS group,RS5 intervention significantly increased the body weight and colon length of mice,significantly decreased DAI score and spleen index,and significantly improved colon injury of colitis mice.RS5 significantly decreased the serum levels of tumor necrosis factor(TNF)-α,interleukin(IL)-1β,and IL-6 in mice with acute colitis.Additionally,RS5 down-regulated the mRNA expression of Il-1β and Il-6 while up-regulating Il-10,zonula occludens-1(ZO-1),Occludin,Claudin-1,Claudin-4,Mucin2(MUC2)and Mucin3(MUC3)in the colon.The RS5 intervention significantly up-regulated the protein expression of ZO-1,Occludin,Claudin-1,and MUC2,while down-regulated the phosphorylation of NF-κB and IκBα as well as the expression of IL-1β in the colon of mice.DSS and RS5 interventions did not have a significant effect on the overall richness and diversity of microbiota,but significantly alter the community composition.At the phylum level,there was a significant increase in the abundance of Verrucomicrobia observed in mice with acute colitis;RS5-intervention significantly increased the abundance of Bacteroidetes.At the genus level,the abundance of Turicibacter,Oscillospira,Odoribacter,and Akkermansia increased,while that of Allobaculum,Ruminococcus,and Coprococcus decreased in the colon of mice with acute colitis;In mice with colitis treated with RS5,the abundance of Allobaculum was partially restored,while the abundances of Akkermansia and Turicibacter were significantly reduced.At the phylum level,the abundance of TM7 exhibited a negative correlation with the pathological score and expression of Il-6,while displayed a positive correlation with the gene expression levels of ZO-1,MUC2,and Il-10.The abundance of Actinobacteria exhibited a negative correlation with DAI score,pathological score,and the gene expression levels of Il-1β and Il-6,while showed a positive correlation with colon length,ZO-1,Occludin,MUC2,and Il-10.Verrucomicrobia abundance was positively correlated with DAI score,pathological score,and the gene expression levels of Il-1β and Il-6,and negatively correlated with colon length,ZO-1,Occludin,claudin-1,MUC2,and Il-10.At the genus level,there was a negative correlation between the abundance of Ruminococcus,Lactobacillus,and Allobaculum and DAI score,pathological score,the gene expression levels of Il-6 and Il-1β,and was positively correlated with colon length,ZO-1,Occludin,claudin-1,MUC2,and Il-10.The abundance of Oscillospira,Turicibacter,Odoribacter,Akkermansia,and Helicobacter was positively correlated with the DAI score,pathological score,and expression levels of Il-6 and Il-1β,while it was negatively correlated with colon length and the gene expression levels of ZO-1,Occludin,claudin-1,MUC2,and Il-10.ConclusionThe formation of RS5 could increase the content of RS and the gelatinization temperature.The crystal structure of RS5 was V type.The RS5 was in the state of coexistence of type I and II complexes.The RS 5 showed a rough surface,compact structure,and outstanding stability.RS5 administration ameliorated the symptoms of DSS-induced acute colitis in mice,including weight loss,DAI score increasing,colon shortening,splenomegaly,and colonic pathological damage.RS5 could protect the integrity of the physical and chemical barrier of the colon,inhibit pro-inflammatory cytokine expression and NF-κB signaling pathway activation,modulate of microbiota composition,and partially ameliorate gut microbiota disorder.