Effect Of Chitosan On Oxidative Stress And Glucose Metabolism In Mice Fed High-Fat Diet

This investigation was conducted to evaluate the effect of chitosan on the oxidative stress and glucose metabolism,by feeding high-fat diet for 16 weeks with chitosan added.This research contributed to the pathology mechanism of oxidative stress and glucose metabolism confusion caused by high-fat diet.It also provided the theoretical basis for chitosan as a nutrient for regulating blood sugar.Method: 60 male C57BL/6J mice(6 week old)were randomly divided into 5 groups(12 per group): control group(normal diet,NF);High-fat diet group(HF);low molecular weight chitosan group(HF+5% LMWC);high molecular weight chitosan group(HF+5% HMWC);metformin group(HF+5% MET).Body weight,food intake,blood sugar,glucose tolerance,insulin tolerance were measured in the process of feeding.All rats were sacrificed after 16 weeks.Triglyceride,total cholesterol,high density lipoprotein cholesterol,low density lipoprotein cholesterol in plasma were measured;triglyceride,total cholesterol,hepatic lipase and lipoprotein lipase level in liver were measured;total antioxidant activity,catalase activity,malondialdehyde,superoxide dismutase activity in liver were measured;structure of liver and pancreas were observed;the mRNA expression of genes in liver related to antioxidant and gluconeogenesis pathway were measured by Reverse Transcription-Polymerase Chain Reaction(RT-PCR);the protein expression of genes in liver related to antioxidant and gluconeogenesis pathway were measured by Western Blot.The results were shown as follows: 1)high fat diet for 16 weeks had no significant effect on daily food intake,but would cause significant weight gain,chitosan could effectively alleviate the phenomenon,the effect of high molecular weight chitosan was better;2)high fat diet for 16 weeks made the ACC1 mRNA expression significantly increase,which was the enzyme related with hepatic lipid synthesis,resulting in the significant increase of the content of TC,LDL-C in serum,the content of TC in the liver increased significantly,chitosan could significantly relieve the phenomenon,the effect of high molecular weight chitosan was better than that of low molecular weight chitosan;3)high fat diet for 16 weeks had a certain damage to the structure of liver and pancreatic tissue,causing fatty degeneration,chitosan could protect the structure of liver and pancreatic tissue;4)high fat diet changed the redox environment of mice,decreased oxidase(CAT,SOD)content,increased MDA content,the Nrf2 mRNA expression increased significantly,while the HO-1,NQO1 mRNA expression decreased significantly,GSK-3β mRNA expression increased significantly.Chitosan could improve the level of oxidative stress,ease the glucose metabolism disorder injury caused by high fat diet;5)high fat diet for 16 weeks caused glucose metabolism disorder,mainly because of oxidative stress in the liver caused by the increased expression of PEPCK and G6 Pase,eventually lead to glucose metabolism disorder in liver and muscle,chitosan could regulate FOXO1 and HNF4α mRNA expression level.Conclusion: High-fat diet resulted in oxidative stress and disturbed the glucose metabolism of mice.Chitosan could improve this phenomenon,high molecular weight chitosan had a better effect.