Effects Of Traditional Chinese Medicine On Liver Glycogen Structure In Type 2 Diabetic Mice

Type 2 diabetes is a group of metabolic diseases characterized by hypoglycemia resulting from insulin deficiency and insulin resistance.Liver glycogen plays a vital role in glucose homeostasis to maintain blood glucose levels within a narrow range.Glycogen is a complex highly branched polymers of glucose,with ?-(1,4)linear linkage and ?-(1,6)branching linkage,together with significant but small amounts of various proteins.The glycogen is present as small ? particles,20-30 nm in diameter,and large ? particles,up to 300 nm in diameter.It has been found that liver glycogen from diabetic mice is more vulnerable to degrade readily into ? particles in DMSO than those in non-diabetic mice.And ? particles degrade more quickly because of its high surface area to volume ratio.It may result in losing control of blood glucose balance and high blood glucose concentration.This thesis is divided into two parts.The first part: STZ/HF induced type 2 diabetic mice and healthy mice liver glycogen structure was analyzed via size-exclusion chromatography(SEC).C57BL/6 mice were given high fat diet for a while,and then injected a low dose of streptozocin(STZ)to destruct islet ? cell function,resulting in diabetes.The results show that ? particles from induced type 2 diabetic mice are easier to be degraded into ? particles after DMSO treat,like from db/db mice,which proves the liver glycogen fragility from type 2 diabetic mice is universal.The second part: In order to verify the relationship between fragile glycogen and diabetes and study the possible mechanism leading to glycogen structure fragility,This research used db/db mice as a type 2 diabetic model and compared liver glycogen molecules structure difference diabetic mice with and without administrated TCM and healthy mice by weight distribution of SEC.Astragalus polysaccharide,berberine,panax notoginseng saponins and pueraria flavonoid were chosen as representative TCM extractions of the four type active ingredients.Astragalus polysaccharide,berberine,and pueraria flavonoid have significantly decreased random blood glucose in db/db mice,in coordination with the fact those three medicines have a lower glycogen content than diabetic mice without drug treatment.The SEC weight distribution of liver glycogen from db/db mice treated those medicines showed TCM improved diabetic glycogen fragility.The results showed drug administration can ameliorate the impaired ? particles,helping regulate blood glucose level and mitigate type 2 diabetic symptoms.The further study need to be done to provide a novel drug target for diabetes.