Study On Protective Effects Of Corn Peptide On Nonalcoholic Fatty Liver Injury

Non-alcoholic fatty liver disease(NAFLD),as a highly prevalent chronic liver disease,has become an increasing threat on human health.Thus,there is an urgent need to solve this problem by seeking a safe,non-side-effect drug or treatment.In recent years,bioactive peptides prepared by enzymatically decomposing food-derived proteins have attracted much attention.As a typical bioactive peptide,corn peptide plays a prominent role in anti-oxidation and liver protection due to its unique amino acid composition,which provides a possibility to intervene in NAFLD.In this study,the NAFLD rat model was built by feeding them with high-fat diet,while the NAFLD cell model was established through using high-concentration fructose to attack human normal hepatocytes.The effects of corn peptide on NAFLD were investigated in terms of the animal,the cell and the mitochondria levels,respectively.The main research contents and results are presented as follows:(1)Study on the protective effects of corn peptide on rats with non-alcoholic liver injury induced by high-fat diet.Results showed that the corn peptide significantly reduced the body weights of rats;the serum aspartate aminotransferase(AST)and alanine aminotransferase(ALT)activities and the lipid droplets in liver slices.The number and size of the bubbles reduced the degree of steatosis,decreased the level of triglyceride(TG),total cholesterol(TC)and low-density lipoprotein cholestero(LDL-C)in serum,and increased the levels of high-density lipoprotein cholesterol(HDL-C)in the serum,indicating that the corn peptide effectively inhibited lipid accumulation and alleviated the liver damage.Corn peptide could also effectively increase the glucose tolerance in rats,enhance the ability of rats to regulate blood sugar,and improve the sensitivity of rats to insulin,alleviating the effect of insulin resistance.In addition,it is also found that corn peptide can increase the activities of superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)in liver and decrease the content of malondialdehyde(MDA),which indicates that the corn peptide had good antioxidant properties and could relieve liver oxidative stress.The preventive effects of corn peptide on fatty liver were due to the therapeutic effect.(2)Study on the protective effect of corn peptide pretreatment on NAFLD model cells.Pretreatment with corn peptide can reduce lipid accumulation in NAFLD model cells;reduce the content of reactive oxygen species(ROS)in NAFLD model cells.It indicated that corn peptide reduced lipid accumulation in hepatocytes and alleviated oxidative stress at the cellular level.The western blot analysis showed that corn peptide increased the expression of SIRT1/PPAR-α and the Nrf2/HO-1 pathway and decreased the expression of SREBP-1c,increasing the energy metabolism and inhibiting the lipid accumulation,the insulin resistance and the oxidative stress,which finally resulted in the inhibition of the NAFLD.(3)Study on the protective effect of corn peptide on mitochondrial function in NAFLD model cells.Resultes showed that corn peptide pretreatment can enhance the number of mitochondria and protein content,increase mitochondrial membrane potential,increase mitochondrial tricarboxylic acid circulation rate and oxidative phosphorylation process,and increase intracellular ATP content,thereby enhancing the hepatocyte energy and lipid metabolisms.It inhibited the occurrence of mitochondria and apoptosis,maintained the normal physiological work of the liver,and achieved the effect on the interference on the development of NAFLD.In summary,corn peptide can interfere the development of mitochondria by inhibiting lipid accumulation,alleviating insulin resistance and oxidative stress,protecting mitochondrial function,and enhancing hepatocyte energy metabolism.