Glutamate Intake And Expression Of ICAM-1,NF-?B P65 By Astrocytes In Mice Core Zones And Marginal Areas Arfter Ischemia Reperfusion

Objectives To investigate changes of the infarct volume,brain tissue cells,astrocytes(AS)morphology and the expression of glial fiber acidic protein(GFAP)in core zone and marginal area with the middle cerebral artery occlusion(MCAO)of mice after cerebral ischemia and reperfusion(CIR).To investigate the expression and mechanism of EAAT-2,NF-?B P65 and ICAM-1 by AS in observation areas after CIR in mice.Methods 1 Selecting male KM mice.CIR model was made by MCAO.CIR group consisted by 1h,4h,10 h,24h,48 h,72h aftercerebral ischemia 2 h(n=9).Six mice ligated the right common carotid artery by 1h ? 4h? 10 h ? 24 h ?48h ? 72 h as SO group(n=6),and the remaining mice were N group(n=9).2 Using 2,3,5-Triphenyltetrazolium chloride(TTC)staining to illustrate the location after CIR and volume in N group and model groups.3 Remaining mice were sacrificed before cardiac perfusion of paraformaldehyde,related brain areas were made a paraffin section.4 Using HE staining method to observe the morphology of brain tissue cells in observation areas of N group and CIR group.5 Using immunohistochemistry to detecte numbers and morphology of GFAP in observation areas at different time points.6 We compared the experssion of EAAT-2,ICAM-1 P65 and NF-?B by AS in observation areas after Immunofluorescence with each groups.7 All experimental data were performed with SPSS software(version 21.0)to compile and analysis.Measurement data were expressed as mean ± standard deviation(SD).Intragroup differences were compared with one-way analysis of variance.Values of P<0.05 were considered to be statistically significant.Results 1 Different degrees of neurological deficts appeared after operation in model groups,neurological deficts did not appear in SO group.2 The cerebral infarction was started at CIR 1h.The largest infarct volume was at CIR 24 h and then gradually reduced(F=745.534,P=0.000).3 The results of HE staining showed that the cells in core zone were swelling and hypertrophy after CIR,and the apoptosis of cells in marginal area increased with the extension of CIR time.4 AS appeared rapid apoptosis after the occurrence of cell swelling and hypertrophy in core zone with a lower GFAP expression level than that of marginal area,and there were significant differences in CIR 4h ? 10 h ? 24 h ? 48 h compared with N group(P<0.05);GFAP expression appeared reactive activation and then morphological changes in marginal area,and then significantly increased,except for CIR1 h,so that there were significant differences between the residual group and the N group(P<0.05).5 The result of GFAP and EAAT-2 immunofluorescent labeling: EAAT-2positive cells were almost co-staind with GFAP,the expression in core zone gradually increased within CIR 24h(P<0.05);positive co-staind cells in marginal area at CIR 72 h were lower than that of CIR 48 h.6 The result of GFAP and ICAM-1 immunofluorescent labeling: only a small portion of ICAM-1 was located on AS;positive co-staind cells increased slightly within CIR 24 h,and then the expression decreased gradually;there was a slight increase within CIR 48 h,and then the expression decreased gradually(P<0.05).7The result of GFAP and NF-?B P65 immunofluorescent labeling: only a small portion of NF-?B P65 was located on AS;positive co-staind cells in both core zone and marginal area were observed at CIR 4h,and the expression of two regions was decreased gradually after CIR 24h;positive co-staind cells in the marginal area were slightly more than that in the core zone.Conclusions The CIR of mice could cause cell damage and activate AS.The reactive activation of AS,especially in marginal area of CIR,might be a cerebral protective defense mechanism,and the degree of the activation affected the survival and repair of brain tissue.AS play dual role after CIR,it can protect brain tissue cells by absorbing glutamate.Simultaneously,inflammatory factors released by AS,such as ICAM-1 and NF-?B P65,could play a bad role.Therefore,AS might play an important role in the morphological and functional plasticity after brain damage in the process of CIR.