Protective Effect And Mechanism Of Chitosan Oligosaccharide On Alcoholic Liver Injury

Alcoholic liver disease(ALD)is a common liver disease that seriously affects human health and lifestyle.Currently,there are no FDA-approved drugs for the treatment of alcoholic liver disease.Therefore,there is an urgent need to develop safe and effective drugs for the prevention and treatment of ALD.Chitosan(CTS)is hydrolyzed to obtain chitosan oligosaccharide(COS).COS has many biological activities such as antibacterial,antioxidant,anti-inflammatory and has important development potential in the biomedical industry.In this study,an alcohol-induced liver injury model was established in vivo and in vitro to explore the protective effects of two different molecular weight chitosan oligosaccharides,COST(MW≤1000Da)and COSM(MW≤3000Da),on alcoholic liver injury,and to further study their specific pharmacological mechanism.In vivo animal activity study: After the intervention of COST and COSM,a one-time gavage of 14 m L/kg BW of 50% ethanol caused acute alcoholic liver injury model.The measurement results of serum ALT,AST,ALP and LDH in mice showed that COST and COSM could significantly reduce their levels,and the high dose was equivalent to the positive drug Bifendate.In addition,lipid peroxidation damage indicators and inflammatory factors were measured in liver injury mice.The results showed that the intervention of COST and COSM significantly decreased the levels of serum TNF-α,IL-1β,IL-6,TC,TG and MDA in liver tissue;significantly increased the levels of antioxidant enzymes GSH,SOD and CAT.The results of liver pathological sections showed that COST and COSM interventions improve hepatic steatosis and inflammatory infiltration.The above results show that COST and COSM can reduce liver oxidative damage,improve liver antioxidant capacity,improve liver steatosis and inflammatory damage,and play a role in protecting alcoholic liver injury,and the effect of COSM is better than COST.In vivo animal mechanism study: Western Blot assay was used to detect related proteins in mouse liver tissue.The assay results show that COSM can significantly reduce the protein expression of the liver metabolic enzyme CYP2E1,inhibit the activation of NF-κB and MAPK signaling pathways,activate the antioxidant signaling pathway Keap-1/Nrf-2/HO-1,and increase the antioxidant capacity of mouse livers,and attenuates liver oxidative stress injury,inflammatory injury and apoptosis.In vitro L02 hepatocyte injury activity study: By using COST and COSM to interfere with alcohol-induced L02 hepatocyte injury model,it was proved that both COST and COSM could significantly reduce the contents of ALT,AST and MDA in hepatocytes,significantly increase the contents of antioxidant enzymes GSH and CAT,and improve the alcohol-induced liver damage.This result is consistent with the results of in vivo animal activity experiments.In vitro study on the mechanism of L02 hepatocyte injury: WB results showed that COSM could significantly inhibit the protein expression of the metabolic enzyme CYP2E1 in L02 hepatocytes,inhibit the activation of NF-κB and MAPK signaling pathways,and activate the antioxidant signaling pathway Keap-1/Nrf-2/ HO-1.It shows that COSM can improve the antioxidant capacity of L02 hepatocytes,reduce inflammation and oxidative damage,and achieve the effect of protecting L02 hepatocytes.The experimental results are consistent with the experimental results of in vivo animal mechanism.To sum up,this study shows from in vivo and in vitro experiments that COST and COSM intervention can reduce liver oxidative stress injury,improve liver antioxidant capacity,improve liver inflammatory injury and apoptosis,and achieve the effect of protecting alcohol-induced liver injury.The specific mechanism of COSM protection against alcohol-induced liver injury is as follows: significantly inhibit the protein expression of the alcohol metabolizing enzyme CYP2E1 and reduce oxidative damage;activate the antioxidant signaling pathway Keap-1/Nrf-2/HO-1 to increase the antioxidant capacity of the liver;inhibit the activation of inflammatory pathways NF-κB and MAPK pathways reduces hepatic inflammatory damage and apoptosis.