Auxiliary Protective Effect Of Vigna Mungo Polysaccharides Against Gastric Mucosal Injury And Its Mechanism

Gastric mucosal injury is a prevalent gastrointestinal disease,characterized by a long treatment period and difficulty in achieving complete cure.Moreover,the drugs used for gastric mucosal injury treatment are expensive,require a long treatment duration,and may induce various side effects.At present,an increasing number of studies suggest that natural product-derived polysaccharides can play a safe and effective role in preventing and treating gastric mucosal injury.Legumes can enhance gastrointestinal motility and improve gastrointestinal diseases in traditional diet therapy.Common legumes such as small black soybeans,cowpeas,peas,and chickpeas have high nutritional value.Polysaccharides are important active components of legumes,possessing various biological activities,including antioxidant,hypoglycemic,immunomodulatory,and gut microbiota-improving functions.Therefore,this study used polysaccharides from small black soybean(Vigna Mungo polysaccharide,VMP),cowpea(Vigna unguiculata polysaccharide,VUP),pea(Pisum sativum polysaccharide,PSP),and chickpea(Cicer arietinum polysaccharide,CAP)to investigate their auxiliary protective effects on ethanol-induced acute gastric mucosal injury in mice and screened out VMP with better protective effects on the gastric mucosa.The potential mechanism underlying the beneficial effects of VMP in the amelioration of gastric ulcers was preliminarily investigated by establishing a rat model of chronic gastric ulcers induced by acetic acid.The main research contents and conclusions of this paper are as follows:(1)To explore the auxiliary protective function of four types of legume polysaccharides against ethanol-induced acute gastric mucosal injury in mice.Polysaccharides were extracted from small black soybeans,cowpeas,peas and chickpeas by water extraction and alcohol precipitation,and their basic nutritional composition,monosaccharide composition and molecular weight distribution were determined.The protective effect of these polysaccharides on ethanol-induced acute gastric mucosal injury in mice and its potential mechanism were explored.The results showed that the sugar contents of VMP,VUP,PSP and CAP were 66.40%,71.79%,67.41% and 53.31%,respectively,and their molecular weight distribution were wide.The monosaccharide compositions of VUP,PSP and CAP were mainly Ara,Gal,and Gal A,belonging to pectin acidic polysaccharides,while VMP was mainly composed of Gal and Man,belonging to neutral polysaccharides.The gastric mucosal injury inhibition rates of VMP,VUP and CAP groups were 37.1%,34.4% and 29.8%,respectively,all of which significantly alleviate the gastric mucosal injury in mice.Among them,VMP was able to reduce the levels of interleukin-6(IL-6)and tumor necrosis factor alpha(TNF-α)in serum,significantly decrease the content of malondialdehyde(MDA)in gastric tissue,and increase the activity of total superoxide dismutase(T-SOD)and the content of reduced glutathione(GSH)in the gastric tissue.Therefore,VMP showed a superior protective effect on gastric mucosa,which may be related to improving the antioxidant capacity of gastric tissue and inhibiting the expression of inflammatory cytokines.(2)To explore the auxiliary protective function of VMP on acetic acid-induced chronic gastric ulcer in rats.The acetic acid-induced gastric ulcer model was used to further explore the protective effect of VMP on gastric mucosa and its potential mechanism by measuring the gastric ulcer area,biochemical indexes and metabolites in serum.The results showed that VMP significantly reduced the ulcer area,promoted ulcer healing,and had an effect equivalent to that of cimetidine,as observed through histological and pathological observations of gastric tissue.Both low-dose(VMP-L)and high-dose(VMP-H)Vigna Mungo polysaccharide significantly increased T-SOD activity and GSH content in gastric tissue,and significantly decreased MDA content,but only VMP-H increased the content of epidermal growth factor(EGF)and vascular endothelial growth factor(VEGF)in gastric tissue.Forthermore,VMP regulated 20 potential biomarkers related to gastric ulcer,and VMP-L had a better effect than VMPH.Specifically,VMP intervention increased antioxidant-related metabolites such as Lglutamine,ascorbic acid and isobutyryl-L-carnitine,and affected various important metabolic pathways.Therefore,the mechanism of VMP promoting gastric ulcer healing may be related to the improvement of the antioxidant capacity of gastric tissue,the release of growth factors,and the regulation of potential biomarkers in the serum.(3)To investigate the regulatory effect of VMP on gut microbiota of rats with chronic gastric ulcer.The feces of gastric ulcer rats were analyzed by 16 S r DNA highthroughput sequencing technology to further explore the effect of VMP intervention on gut microbiota of gastric ulcer rats.The results showed that VMP significantly increased the content of total short-chain fatty acids(SCFAs)in colonic contents of rats with gastric ulcer,including the levels of acetic acid,propionic acid,isobutyric acid,valeric acid and isovaleric acid,and the content of total SCFAs in VMP-H group was significantly higher than that in VMP-L group.In addition,VMP had no significant effect on the Alpha diversity index of gut microbiota in rats with gastric ulcer,but Beta diversity analysis showed that the gut microbiota structure of VMP group was more similar to that in the normal group.VMP effectively ameliorated gut microbiota dysbiosis in gastric ulcer rats by reducing the relative abundance of Firmicutes,Lachnospiraceae＿NK4A136＿group,Quinella and Lactobacillus,while increasing the relative abundance of Bacteroidota,Bacteroides,Oscillospiraceae＿UCG-005,Muribaculaceae,Parasutterella and Ruminococcus.Moreover,Parasutterella and Lachnospiraceae＿NK4A136＿group were significantly correlated with SCFAs and various serum metabolites.Therefore,VMP may facilitate the repair of gastric ulcers by modulating the relative abundances of key microbial communities such as Bacteroidota,Firmicutes,Parasutterella and Lachnospiraceae＿NK4A136＿group,promoting the production of SCFAs,and influencing changes in serum metabolites.In summary,this study compared the auxiliary protective effects of VMP,VUP,PSP and CAP on ethanol-induced acute gastric mucosal injury in mice,and found that VMP had the best preventive effect.Then,through the rat model of chronic gastric ulcer induced by acetic acid,it was found that VMP could promote the healing of gastric ulcer.The mechanism may be related to enhancing the antioxidant capacity of gastric tissue,promoting the release of growth factors and regulating the content of potential biomarkers in the serum.In addition,VMP can also restore the gut microbiota stability of gastric ulcer rats by promoting the production of SCFAs and regulating the relative abundance of key microbial communities such as Bacteroidota,Firmicutes,Parasutterella and Lachnospiraceae＿NK4A136＿group,thereby accelerating the healing process of gastric ulcers.This study aims to provide theoretical basis for the development and application of polysaccharides from legumes as health foods or food additives for protecting gastric mucosa,and provide references for the diversified development and high value-added utilization of legume resources.