| Aim:To study the effects of liraglutide on the surface markers CD16 and MHCII of M1type microglia/macrophage,CD206 and Arg-1 of M2 type microglia/macrophage,pro-inflammatory factor interleukin(IL)-1β,anti inflammatory factor IL-10 and peroxisome proliferator activated receptorα(PPARα)after focal cerebral ischemia injury in diabetic rats.Further to explore the neuroprotective mechanism of liraglutide,as well as to provide theoretical basis and laboratory basis for clinical treatment of patients with diabetes mellitus complicated with cerebral infarction.Methods:Seventy-five healthy male Sprague-Dawley(SD)rats(8-12 weeks old,280-320g)were randomly divided into 5 groups:cerebral infarction(CI)group,diabetic cerebral infarction(DCI)group,insulin treatment(Ins)group,liraglutide treatment(Lir)group and liraglutide+PPARαantagonist GW6471(Lir+GW6471)group.Each group consisted of15 rats.The diabetic rat model was induced by intraperitoneal injection of streptozotocin(STZ)(50mg/kg)after 4 weeks of high glucose and high fat diet in ordinary rats.Then the permanent middle cerebral artery occlusion(p MCAO)model was established by modified Zea Longa line embolization.Rats in Lir+GW6471 group were injected with GW6471(10μg,dissolve in 5μL 2%dimethyl sulfoxide(DMSO)).After successful p MCAO modelling,liraglutide(700μg/kg/d)was injected intraperitoneally in the left lower abdomen.The remaining four groups of rats were injected with the same volume of 2%DMSO in the left lateral ventricle 30 minutes before p MCAO.After successful p MCAO modelling,rats in the Lir group were injected with liraglutide(700μg/kg/d)into the left lower abdomen;rats in the Ins group were injected with insulin(2U/kg/d)into the left lower abdomen;rats in the CI group and DCI group an equal volume of normal saline were injected intraperitoneally into the left lower abdomen.At 72h after the successful p MCAO,the neurological deficits of rats were evaluated,and then rats were sacrificed,2,3,5-chlorinated diphenyltetrazolium(TTC)staining was used to detect the volume of cerebral infarction;Real Time quantitative PCR(RT-q PCR)was used to detect the expression of PPARα,M1 type microglia/macrophage surface markers CD16,MHCII and M2 type microglia/macrophages surface markers CD206,Arg-1 m RNA in ischemic brain tissues;western blot(WB)was used to test the relative expression of IL-1β,IL-10 and PPARαin ischemic brain tissue;immunofluorescence double-labeling method was used to determine the number of positive cells of M1 type microglia/macrophage surface marker Iba-1+CD16/32 and M2 type microglia/macrophage surface marker Iba-1+CD206.Results:1.Fasting blood glucose changes:DCI group,Ins group,Lir group,and Lir+GW6471 group after STZ injection,the random blood glucose level was significantly increased(P<0.05).72h after p MCAO,the blood glucose levels of Ins group,Lir group and Lir+GW6471 group decreased significantly(P<0.05).2.Neurological impairment score:Compared with the CI group,the score of the DCI group was significantly higher(P<0.05).Compared with the Ins group,the score of the DCI group was not significantly changed(P=0.784).The Lir group was compared with the DCI group and Lir+GW6471 group,the scores were significantly lower(P<0.05).3.Cerebral infarction volume:Compared with the CI group,the DCI group had a significant increase in cerebral infarction volume(P<0.05).Compared with the Ins group,the DCI group had no significant changes in cerebral infarction volume(P=0.101).The Lir group was more infarcted than the DCI group the volume was significantly reduced(P<0.05).Compared with the Lir group,the infarct volume in the Lir+GW6471 group was significantly increased(P<0.05).4.PPARα:Compared with the CI group,the PPARαm RNA expression in the DCI group was significantly reduced(P<0.05).Compared with the DCI group,the PPARαm RNA expression in the Lir group was significantly increased(P<0.05),while the Lir+GW6471group Compared with the Lir group,the expression of PPARαm RNA was significantly reduced(P<0.05).Compared with the CI group,the DCI group PPARαwas significantly reduced(P<0.05).Compared with the DCI group,the Lir group PPARαwas significantly increased(P<0.05),while the Lir+GW6471 group was significantly lower than the Lir group(P<0.05).5.M1 type microglia/macrophages:Compared with the CI group,the expression of CD16and MHCII m RNA in the DCI group increased significantly(P<0.05).While the Lir group was compared with the DCI group and the Lir+GW6471 group,the expression of CD16 and MHCII m RNA expression were significantly reduced(P<0.05).Iba-1+CD16/32 positive cell number expression:Compared with the Lir group,the number of Iba-1+CD16/32positive cells/mm~2 in the DCI group and the Lir+GW6471 group was significantly increased(P<0.05).6.M2 type microglia/macrophages:Compared with the CI group,the expression of CD206and Arg-1 m RNA in the DCI group was significantly reduced(P<0.05).While the Lir group was compared with the DCI group and Lir+GW6471,the expression of CD206 and Arg-1m RNA increased significantly(P<0.05).Iba-1+CD206 positive cell number expression:Compared with the Lir group,the number of Iba-1+CD206 positive cells/mm~2 in the DCI group and the Lir+GW6471 group was significantly reduced(P<0.05).7.IL-1β:Compared with the CI group,the expression of IL-1βin the DCI group was significantly increased(P<0.05).While the expression of IL-1βin the Lir group was significantly reduced compared with the DCI group and the Lir+GW6471 group(P<0.05).8.IL-10:Compared with the CI group,the expression of IL-10 in the DCI group was significantly reduced(P<0.05).While the expression of IL-10 in the Lir group was significantly increased compared with the DCI group and the Lir+GW6471 group(P<0.05).Conclusion:1.Liraglutide has neuroprotective effect in diabetic cerebral infarction rats;2.It may be one of the neuroprotective mechanisms that by activating PPARαto inhibit the conversion of microglia/macrophages to the M1 type and promote the conversion of microglia/macrophages to the M2 type. |
PDF Full Text Request