Protection Effects Of Gastric Acid-response Marine Biohydrogel On Alcohol-induced Injury

In the process of communication,wine culture often forms a kind of table culture.A little drink is good for one’s feelings,while a lot of drink is harmful to one’s health.Firstly,excessive alcohol intake directly stimulates the human gastric mucosa,which causes gastritis,gastric ulcer,gastric perforation,bleeding,etc.What’s more,acetaldehyde,a metabolite of alcohol,can cause liver steatosis,alcoholic fatty liver,hepatitis,liver fibrosis,and cirrhosis;Meanwhile,it will affect the nervous system and urinary system.In this paper,the hydrogel precursor solution was obtained by preparing N-acetylcysteine grafted chitosan（shell）-calcium carbonate（core）coated particles[CS-NAC（CaCO₃）],dispersing them uniformly into sodium alginate（SA）solution,and finally adding tilapia collagen peptide（TCP）,which formed hydrogel in situ upon encountering gastric acid（CS-NAC/SA/TCP）.The chemical structure,microscopic morphology,in vitro adhesion,biocompatibility,and degradability of CS-NAC/SA/TCP were systematically investigated.Base on this,the protective functions of CS-NAC/SA/TCP on alcohol-induced gastric,liver,and brain injury were investigated.The main research contents and results are as follows:（1）Chitosan（CS）was sulfhydryl-functionalized to obtain CS-NAC and used to coat nano-CaCO₃to form CS-NAC（CaCO₃）,which were characterized by chemical structure.By analyzing the results of infrared spectroscopy（FTIR）and proton nuclear magnetic resonance spectroscopy（¹H NMR）of CS-NAC,it can be proved that CS-NAC has been successfully prepared with a degree of substitution of 9.00%.Through the analysis of FTIR,scanning electron microscope（SEM）,and particle size and zeta potential of CS-NAC（CaCO₃）,it can be proved that CS-NAC and nano-CaCO₃ have formed CS-NAC（CaCO₃）through the adhesion of CS-NAC and electrostatic interaction between them.（2）CS-NAC（CaCO₃）was uniformly dispersed in SA solution,and TCP was added to prepare hydrogel precursor solution by polyelectrolyte blending（PEC）.It could form CS-NAC/SA/TCP in situ in the presence of gastric acid.Based on the single-factor test results,the preparation conditions were optimized by the Box-Behnken experimental design.The results showed that the optimal conditions for the preparation of CS-NAC/SA/TCP were SA concentration of 1%,M_CS-NAC/MCaCO₃of 1:1,and MSA/MCS-NAC（CaCO₃）of 15:1.（3）The optimized CS-NAC/SA/TCP was carried out by FTIR and external morphology.Besides,the in vitro properties of CS-NAC/SA/TCP,such as ethanol adsorption,swelling,degradation,active peptide release,adhesion,and antioxidant properties,were also analyzed.The results showed that CS-NAC/SA/TCP exhibited irregular porous structure with favorable ethanol adsorption and swelling properties,with ethanol adsorption and swelling rates of 56.23%and 2350.00%,respectively;favorable mechanical properties and gastric mucosal adhesion with mucosal adhesion of 50.81±3.43%;excellent antioxidant activity,the IC50 of 1,1-diphenyl-2-picrylhydrazyl free radical（·DPPH）,peroxide-free radical(O₂^·-)and hydroxyl radical（·OH）were 2.20,2.15 and 1.26 mg/m L,respectively;fine sustained release with a cumulative release of 95.20%in 6 hours;better biodegradability and can be completely degraded in simulated body fluids within 3 days.（4）In acute and chronic alcohol-induced gastric mucosal injury experiments in mice,by observing the survival rate and body weight changes;observing the gastric mucosal congestion and inflammatory cell infiltration;examining the activities of antioxidant factors,the expression of inflammatory factors,and the protective factors of the gastric mucosa to investigate the therapeutic effects of CS-NAC/SA/TCP on the alcoholic gastric mucosal injury.The results showed that CS-NAC/SA/TCP made no difference to the survival curve and body weight change of mice.It could improve the antioxidant system in mice of the content of superoxide dismutase（SOD）,catalase（CAT）,and glutathione（GSH）in tissues to scavenge the excess free radicals caused by alcohol,inhibiting the expression of pro-inflammatory cytokines interleukin 1β（IL-1β）and interleukin 6（IL-6）,and increasing the production of gastric mucosal protective factors prostaglandin E2（PGE2）and nitric oxide（NO）so that protect and repaired alcohol-induced gastric mucosal injury of the mice.（5）In the experiment of acute alcohol-induced liver injury in mice,by detecting the changes of the liver index;pathological observation of hemorrhage and inflammatory cell infiltration in mouse liver tissues;detecting the changes of serum transaminase activities and checking out the changes of metabolic enzymes activities in the liver so that the effects of CS-NAC/SA/TCP on the alcohol-induced liver injury was discussed.It can be concluded from the results that CS-NAC/SA/TCP significantly improved alcoholic liver injury from the pathological point of view.It dramatically reduced the serum levels of glutamic alanine transaminase（ALT）and glutamic oxalacetic transaminase（AST）.It enhanced alcohol dehydrogenase（ADH）and acetaldehyde dehydrogenase（ALDH）in the liver of mice,thus can reducing alcoholic liver injury.（6）The therapeutic effects of CS-NAC/SA/TCP on alcoholic brain injury were investigated by examining the changes of brain index and assessing the memory ability of mice in the Morris water maze experiment in a chronic alcoholic brain injury experiment.The results showed that CS-NAC/SA/TCP could relieve the symptoms of brain edema caused by excessive alcohol consumption and improve the memory ability of mice in the Morris water maze experiment.Therefore,CS-NAC/SA/TCP has protective and therapeutic effects on mice with alcoholic brain injury.