Effects And Mechanisms Of Lycium Barbarum Polysaccharide On Streptozotocin-induced Vasodilatation Dysfunction

ObjectiveTo observe the changes of vascular function in rats induced by Streptozotocin(STZ)and to further explore the protective effect of Lycium barbarum polysaccharides(LBP)on stz-induced vascular function and its possible mechanism.MethodsForty male Sprague-Dawley(SD)rats were randomly divided into 4 groups(n = 10): the control group,stz group,stz plus LBP(LBP,30 mg/kg/day,i.g),stz plus LBP(LBP,60 mg/kg/day,i.g).Rats treated with STZ(50 mg/kg/d)for 5days,and then measured the blood glucose,higher than 16.7mmol/L as a criterion for diabetes,the experimental group diabetic rats were treated with LBP.The blood glucose,cholesterol and triglyceride values were measured,the vascular reactivity of aortas was determined.The level of superoxide anion in rat thoracic aorta was evaluated by hydroethidine(DHE).The vascular morphology was observed by hematoxylin and eosin(HE)staining.The conten of TNF-α and IL-6 in serum was determined by ELISA,The expression of ICAM-1 and VCAM-1 in aorta was measured by immunohistochemistry assay.The protein expression of calpain-1,VCAM-1,ICAM-1,IL-6,eNOS and TNF-αdetected by western blot.the mRNA expression of MMP-2 was determined by RT-PCR.ResultsCompared with the Control group,the STZ-induced rats:(1)the fasting blood glucose,triglyceride and cholesterol levels increased significantly;(2)The range of smooth muscle cell in rats was in disorder;(3)The protein expression of calpain-1,VCAM-1,ICAM-1,IL-6 and TNF-α was increased in aortas,while the protein expression of eNOS was decreased;(4)The contents of IL-6 and TNF-αin the serum were increased;(5)the m RNA expression of MMP-2 was increased;(6)the vascular diastolic function was significantly impaired.However,treatment with lbp could reverse these changes.ConclusionLBP can improve the vascular dysfunction in STZ-induced diabetic rats,which may be related to the inhibition of oxidative stress on endothelial injury,and the reduction of inflammatory infiltration and fibrosis.