| Alcohol-induced liver damage（ALD）is a devastating liver disease caused by long-term or heavy alcohol consumption,which is one of the important sources of non-viral liver injury.The pathological characteristics of ALD are mainly fat accumulation in the liver in the early stage,which gradually develops into steatohepatitis,liver fibrosis and cirrhosis.However,the pathogenesis of ALD is very complex,and there is no targeted treatment drug.Therefore,the prevention or improvement of ALD is still a great challenge in today’s world.Food-borne functional factors are considered as potential therapeutic agents to enhance human health due to their low antigenicity,high absorbability and wide range of sources.As potential functional components in the food industry,food-borne functional factors have a good application prospect and are of great significance to improve the health of all people.In this paper,Jinhua ham was used as raw material to explore the effects of oligopeptide and fatty acid in Jinhua ham on ALD in mice and its mechanism by constructing an alcohol-induced liver damage model in mice.The main functional factors in Jinhua ham that can improve alcohol-induced liver damage and their characteristics were elucidated by stepwise evaluation.Finally,a functional food can be developed to prevent and ameliorate alcohol-induced liver damage.In order to provide an economic and feasible dietary intervention strategy for the prevention and improvement of alcohol-induced liver damage.Detailed research contents and results are as follows:（1）Effects of oligopeptide in Jinhua ham on alcoholic liver injury and its mechanism.The present study aimed to investigate the protective activity of peptides isolated from Jinhua ham（JHP）on alcoholic liver disease（ALD）and the mechanisms of the JHP to prevent and protect ALD.The results showed that the primary structure with the strongest liver protective activity of peptides was Lys-Arg-Gln-Lys-Tyr-Asp（KRQKYD）,which was derived from myosin of Jinhua ham.Further,the mechanism of KRQKYD prevention and protection of ALD was attributed to the fact that KRQKYD increase the abundance of Akkermansia muciniphila in the gut and decrease the abundance of proteobacteria（especially Escherichia＿Shigella）by scavenging reactive oxygen radicals.It reduced LPS-induced liver inflammation cascade by protecting the intestinal barrier,increasing the tight connection of intestinal epithelial cells and reducing the level of LPS in portal venous circulation.KRQKYD can inhibit the production of ROS by upregulating the expression of NFR2/HO-1 antioxidant defense system,and reduce oxidative stress injury of liver cells.The decrease of ROS and cell pro-inflammatory cytokine TNF-αdown-regulates the expression of SREBP1c,reduces the lipid synthesis in liver,and prevents the lipid accumulation induced by alcohol in liver.The findings suggest that Jinhua ham can be used as a new source of bioactive peptides for the protection from alcohol-induced liver damage.（2）Stability and transepithelial transport of oligopeptide（KRQKYD）with hepatocyte-protective activity from Jinhua ham in human intestinal Caco-2 monolayer cells.The study evaluated the stability of an oligopeptide（KRQKYD）and its transport mechanism by simulating gastrointestinal digestion and a model of human intestinal Caco-2 monolayer cells in vitro.In this study,the effects of environmental factors（temperature,p H and Na Cl concentration）and simulated gastrointestinal digestion on the stability of KRQKYD were evaluated by indicators of the levels of ALT,AST and MDA in an alcohol-induced hepatocyte injury model.The results showed that KRQKYD still maintained satisfactory hepatocyte-protective activity after treatment with different temperatures（20-80℃）,p H（3-9）,Na Cl concentration（1-7%）and simulated gastrointestinal digestion,which indicated that KRQKYD showed good stability to environmental factors and simulated gastrointestinal digestion.Furthermore,the intact KRQKYD could be absorbed in a model of Caco-2 monolayer cells with a Papp value of（9.70±0.53）×10-7 cm/s.Pretreatment with an energy inhibitor（sodium azide）,a competitive peptide transporter inhibitor（Gly-Pro）and a transcytosis inhibitor wortmannin did not decrease the level of transepithelial KRQKYD transport,indicating that the transport mechanism of KRQKYD was not associated with energy dependent,vector mediated and endocytosis.The tight junction disruptor cytochalasin D significantly increased the level of transepithelial KRQKYD transport（P<0.05）,suggesting that intact KRQKYD was absorbed by paracellular transport.（3）Effect of fatty acids in Jinhua ham on alcoholic liver injury and its mechanism.The pathological characteristics of alcohol-associated liver damage（ALD）mainly include liver lipid accumulation,which subsequently leads to alcohol-associated steatohepatitis,fibrosis and cirrhosis.Dietary factors such as alcohol and fat may contribute to the development of ALD.A chronic alcohol-fed mouse model was used to investigate the effect of fatty acids in Jinhua ham on ALD.The fatty acids in Jinhua ham could prevent the occurrence of ALD from chronic alcohol consumption.In addition,the fatty acids in Jinhua ham with liver protective activity were long-chain saturated fatty acids（LCSFAs）,including palmitic acid and stearic acid.In contrast,long-chain polyunsaturated fatty acids aggravated the pathogenesis of ALD.Furthermore,the mechanism underlying the prevention of ALD by fatty acids in Jinhua ham was ascribed to increasing relative abundances of Akkermansia muciniphila and Lactobacillus in the gut,which were beneficial to regulating intestinal homeostasis,ameliorating intestinal barrier dysfunction and reducing alcohol-associated hepatitis and oxidative stress damage.This study demonstrated that dietary supplementation with saturated fatty acids could prevent or mitigate ALD by regulating the gut microbiota（GM）and improving the intestinal barrier,while provided a more affordable dietary intervention strategy for the prevention of ALD.（4）Effect of W/O emulsion prepared from Jinhua ham fat and oligopeptide on alcohol-induced liver damage and its mechanism.The aim of this study was to preparate W/O emulsion encapsulate R8-modified KRQKYD for ameliorating alcohol-induced liver damage and clarify the mechanism underlying the prevention of alcohol-induced liver damage（ALD）.A chronic alcohol-fed mouse model was used to investigate the effect of W/O emulsion on ALD.The results shown that the W/O emulsion could prevent the occurrence of ALD from chronic alcohol consumption.Furthermore,the mechanism underlying the prevention of ALD by W/O emulsion was ascribed to increasing relative abundances of Akkermansia muciniphila and Lactobacillus in the gut,which were beneficial to regulating intestinal homeostasis,ameliorating intestinal barrier dysfunction and reducing alcohol-associated hepatitis and oxidative stress damage.This study demonstrated that dietary supplementation with W/O emulsion could prevent or mitigate ALD by regulating the gut microbiota（GM）and improving the intestinal barrier,while provided a feasible strategy for oral administration oligopeptide to ameliorate ALD. |
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