Abstract: The experiment mean to explore the improving insulin resistance (IR) mechanism of Lycium barbarum polysaccharide-4a (LBP-4a) in non-insulin dependent diabetes mellitus (NIDDM) rats. LBP was extracted from Ningxia-Lycium barbarum by water extraction and ethanol precipitation technique. And the ingredient of LBP-4a was obtained by separation and purification. The animal model of NIDDM was made by feeding high-glucose and high-fat diet and subjecting to.i.p.little-dose streptozotocin (STZ). The rats of NIDDM model were divided into four groups, including model group, LBP-4a low-dose and high-dose groups, rosiglitazone group and normal control group. In order to research the effect of LBP-4a on reducing blood glucose and ameliorating IR in NIDDM rats, a lot of techniques were used such as Single Cell Gel Electrophoresis et al. We studied systematically the effect of LBP-4a on IR in NIDDM rats and researched the mechanism. The results indicated that LBP-4a had lipid-lowering effects on NIDDM rats. Furthermore, LBP-4a had antioxidative function and repairing DNA damage on NIDDM rats.Therefore, LBP-4a as a dietary supplement may improve IR and prevent the development of complications or even tendency to carcinogenesis in NIDDM rats.

Key words: lycium barbarum polysaccharide-4a; non-insulin dependent diabetes mellitus; insulin resistance; DNA damage