Effect Of Macrophage Migration Inhibitory Factor On Nerve Injury Induced By Cerebral Ischemia-reperfusion In Rats

Background:Ischemic stroke result in permanent necrosis of brain tissue in arterial perfusion area by various causes of brain blood supply interruption.In recent years,it has been found that macrophage migration inhibitory factor(MIF)may be involved in the occurrence and development of stroke.However,the mechanism of MIF in ischemic stroke has not been elucidated.Objective:To investigate the effect of MIF on nerve injury after cerebral ischemia-reperfusion injury(I / R)in rats and its potential mechanism.Methods:42 male SD rats were randomly divided into sham group(sham),ischemia-reperfusion group(I / R)and MIF inhibitor ISO-1 treatment group(ISO-1).Middle cerebral artery occlusion(MCAO)was used to establish ischemia-reperfusion model in rats.Rats in ISO-1 group were intraperitoneally injected with ISO-1 at the same time of reperfusion.Garcia score and balance beam walking test score were used to evaluate the neurologic impairment of rats in each group.2,3,5-triphenyltetrazolium chloride(TTC)staining was used to evaluate the area of cerebral infarction.Nissl staining was used to observe the morphology of neurons.TUNEL staining was used to detect the apoptosis of neurons.Immunofluorescence staining was used to observe the expression changes of MIF in glial fibrillary acidic protein(GFAP),Ionized calcium binding adaptor molecule-1(Iba-1)and neuronal nuclear antigen(Neu N)in cerebral cortex.Detecting the expression of MIF,AMP-activated protein kinase(AMPK),lactate dehydrogenase A(LDHA),pyruvate kinase M2(PKM2)and glucose transporter-1(GLUT-1)in brain tissue by Western Blot.Results:Compared with sham group,MIF of I/R rats increased significantly in the peri infarct area and decreased significantly in the infarct core.MIF in the infarct core was mainly located in neurons,some in astrocytes,and a few in microglia.Compared with sham group,the infarct volume and balance beam increased,while Garcia score decreased in I / R group and ISO-1 group(P < 0.05).Compared with I /R group,the infarct volume and balance beam decreased,while Garcia score increased in ISO-1 group(P < 0.05),which indicated that ISO-1 could reduce the infarct size and improve the neurological function damage after stroke.In sham group,Nissl bodies were round and round like,with loose cytoplasm and uniform distribution;In I / R group,Nissl bodies were deeply stained,reduced in volume and number,long fusiform and scattered;Compared with the I / R group,the Nissl body of ISO-1 group recovered partially.Compared with sham group,the total apoptotic rate,neuronal apoptotic rate,apoptotic protein Bax and caspase-3 increased in I / R group(P < 0.05).Compared with I / R group,the total apoptotic rate,neuronal apoptotic rate,apoptotic protein Bax and caspase-3 were decreased in ISO-1 group(P <0.05).There was no significant difference in anti-apoptotic protein Bcl-2 among the three groups.Immunofluorescent and Western blot showed that compared with Sham group,the proliferation and activation of astrocyts were increased in I/R group and ISO-1group(P<0.05).Compared with the I/R group,the proliferation and activation of astrocyts were decreased in the ISO-1 group(P<0.05).Western blot showed that compared with Sham group,the expression of p-AMPK/AMPK,LDHA,PKM-2 and GLUT-1 was up-regulated in I/R group and ISO-1 group(P<0.05).Compared with I/R group,the expression of p-AMPK/AMPK,LDHA,PKM-2,GLUT-1 protein was decreased in ISO-1 group(P<0.05).Conclusion:MIF inhibitor ISO-1 plays an important positive regulatory role in the recovery of neurological function after ischemia-reperfusion in MCAO rats,which may be related to the molecules involved in glucose metabolism.