Abstract: Objective To study the protective effect of chitosan oligosaccharides on mouse nonalcoholic fatty liver disease. Methods 75 KM mice were randomly divided into 5 groups. Three sample groups and the model group were given with a high-fat diet daily for 8 weeks, while the negative group was given ordinary diet consecutively. Three sample groups of mice were given different doses of samples by oral gavage for 30 days after nine weeks. The animals of the negative control group and the model control group were simultaneously given equal amounts of pure water. At the end of the experiment, the animals were weighed and fasted for 16 hours. On the 31st day, the animals were anesthetized and killed. Blood samples were collected. We performed anatomical observation and histopathology examination on the liver tissue. Simultaneously take some liver tissue homogenate and examine changes in levels of TG, GSH, MDA, TNF-α、TGF-β and IL-6 in it. Methods After administering different doses of chitosan oligosaccharides to mice by oral gavage for 30 days ,the level of AST, TGF-β and TNF-α (68.0±5.4 U/L, 62±5.0 pg/mL, 52±3.0 pg/mL)in liver tissue of medium dose group,and the level of TG(0.25±0.15 mmol/L), MDA(2.3±0.75 nmol/L), IL-6(2.8±0.3 pg/mL), ALT(35.5±2.7 U/L) in the liver tissue of high-dose groups are decreased(AST 89.5±9.4 U/L,TGF-β 75±4.2 pg/mL, TNF-α 60±5.3 pg/mL, TG 0.3±0.1 mmol/L)(P<0.05)compared with the model group, while the concentration of GSH in the medium and high-dose groups (Medium 2.0±0.4 μmol/gprot , High-dose 2.1±0.8 μmol/gprot) is increased (P<0.05) , the results of liver pathology examination showed that the distribution, range, and area of lipid droplets in the medium and high-dose groups were lower than those in the model control group (P<0.05). Conclusion Chitosan oligosaccharides display an auxiliary protective effect on non-alcoholic fatty liver disease.

Key words: Nonalcoholic fatty liver disease, Inflammation, Chitosan oligosaccharides, Immunity, Liver function, Antioxidant