Under Hypoxia In The Rat Cerebral Cortex Astrocytes Of Il-1¦Â And Cd44 Expression And Its Significance

Injury in central nervous system(CNS) and occurance of cerebral diseases are resulted from cell death in brain. Recently, It has become increasingly evident that the inflammatory response plays an important role in the pathogenesis of cerebral lension following ischaemic stroke. Infiltration of leukocytes early in the ischaemic region and development of brain oedema characterises the ischaemia-induced inflammation. Moreover, the resident cells of the brain including astrocytes, microglia and endothelial cells become activated in response to the ischaemic injury. Much of this inflammatory response appears to be mediated by pro-inflammatory cytokines. Interleukin-1β(IL-1β)has an important role during the ischaemic damage as a key pro-inflammatory cytokine. Up-regulation of IL-1β after the insult of cererbral ischemia directly influence the formation of infarction. CD44 is a family of cellular adhesion molecular as the major cell-surface receptor for Hyaluronic acid(HA). CD44 plays an important role in the cellular proliferation and mediates the cell-matrix interactions involved in tumor formation and metastasis, and CD44-HA interactions have been implicated in inflammatory-related diseases.Recently, CD44 was implicated the involvement of the ischaemic damage in the model of MCAO. As we know, astrocyte plays an important role in the brain functions as a major cell population in brain, and astrocyte have different functions under distinct pathololgical conditions. Therefore, questiones remain unknown: What would happen to astrocyte in expression of IL-1β and CD44 under hypoxia? And what would be the significance if the changes happened in astrocyte.In order to answer these questions, astrocyte was studied in vitro.Experiment was designed to detect the expression level of IL-1β,CD44v6,CD44 and HAS-2 by double-labeled immunofluorescence,semi-quantitative RT-PCR and western blot. Astrocyte was exposed to the oxygen-glucose deprivation and reoxygenation lh,3h,6h,12h,24h respectively. Compared with the control culture, the result shows that in the transcription level,IL-1βmRNA,CD44mRNA, CD44v6mRNAand HAS-2 mRNA obviously increased after hyoxia and reoxygenation. In the protein level,increase in IL-1B expression has been observed from 6h to 24h, and CD44 had time-dependant increasingly expression after hypoxia and reoxygenation. Our results suggest the differential expression of IL-1B and CD44 on astrocyte under hypoxia and reoxygenation. Our research implyed that the role of IL-16 in ischemic brain injury might be associated with the expression of some adhesion moleculars such as CD44, and the change in ECM level such as the HA might be a important factor in the inflammatory response after ischemic injury.