Lycium Barbarum Polysaccharides Decreases Hyperglycemia-Aggravated Ischemic Brain Injury And Its Influence On Opa1 And Drp1 Expression

Object LBP has been reported to have neuroprotective effect and little is known about improving h ypergl ycemia-aggravated cerebral ischemia reperfusion injury.To explore the mechanism of hypergl ycemia-aggravated ischemic brain injury and the effect of Lycium barbarum polysaccharide pre-treatment in the hypergl ycemia-aggravated ischemic brain injury and its possible mechanism.Methods Diabetic rats were established by intraperitoneal in jection of streptozotocin(STZ).Middle cerebral artery occlusion(MCAO)were used to prepare focal cerebral ischemia reperfusion model,and then reperfusion of 24 h,72h.Experimental groups:(1)MCAO in normogl ycemic rats(NG);(2)MCAO in hypergl ycemic rats(HG);(3)MCAO in hypergl ycemic rats pretreated with LBP(LBP);(4)MCAO in hypergl ycemic rats pretreated with insulin(Insulin).Each group was further divided into 3 subgroups according to reperfusion time-points(sham,24-and 72-h).Comparative observation on body weight,blood glucose,neurological function,infarct volum e,histological,histochemical and optic atrophy 1(optic atrophy 1,Opa1),d ynamin related protein 1(dynamin-related protein1 Drp1)expression.Results The blood glucose of HG group was obviously higher than NG group and the weight of HG group was lower than NG group.LBP pretreatment group lower blood glucose than that of group HG at 1 weeks and 4 weeks(P<0.05).After reperfusion of 24 h,72h,the scores of neurological impairment in HG groups were significantl y higher than NG group.LBP pretreatment group and insulin pretreatment group were significantly lower than H G group(P<0.05).The infarct volume in HG group was significantl y larger than NG group at 24 h after cerebral ischemia and reperfusion,and the infarct volume was decreased in the Lycium barbarum pol ysaccharide pretreatment group and the insulin pretreatm ent group(P<0.05).The histopathological and histochemical results showed that compared with the NG group,the HG group showed a n increasing p yknosis and necrosis in the ischemic and penumbra regions,and an obvious interstitial edema(P<0.05).Compared with the HG group,the Lycium barbarum pol ysaccharide pretreatment group reduced the number of pyknosis neurons(P<0.05).Immunohistochemistry and Western blotting showed that compared with NG group,HG group showed increased expression of mitochondrial fis sion factor Drp1 and decreased expression of mitochondrial fusion factor Opa1(P<0.05).Compared with the HG group,Lycium barbarum polysaccharide pretreatment could down-regulate the expression of Drp1 and up-regulate the expression of Opa1(P<0.05).Conclusion Hyperglycemia aggravate cerebral ischemia / reperfusion injury and associated with increased mitochondrial fission and decreased mitochondrial fusion;Lycium barbarum polysaccharide can reduce h yperglycemia-aggravated ischemic brain injury thro ugh promoting the mitochondria fussion and decreasing the mitochondria fusion.