Production of macrophage inflammatory protein-2 following hypoxia/reoxygenation in glial cells.
Polymorphonuclear neutrophils (PMNs) are known to mediate brain inflammation following hypoxia/reoxygenation (H/R), but the precise mechanisms leading to PMN recruitment are undefined. The alpha-chemokine macrophage inflammatory protein-2 (MIP-2) has specificity for the recruitment of PMNs. In this study, we found that 8 or 12 h of hypoxia followed by 24-h reoxygenation (H8/R24 or H12/R24) induced MIP-2 secretion in cultures of enriched microglia or mixed glia, respectively. Microglia, however, could not survive longer duration (>12 h) of hypoxia. Astrocytes did not produce any significant amount of MIP-2 even though astrocytes maintained 98-99% viability following H12/R24. We also found that microglia survived the H/R treatment better (following H24) in the presence of astrocytes (mixed glial culture) than in microglia-enriched culture. Reoxygenation for prolonged periods (3 and 5 days) following H24 resulted in progressively larger increases in MIP-2 production (20- and 60-fold, respectively) in mixed glial cultures. Immunocytochemical staining revealed that the cells expressing MIP-2 in response to H/R were microglia rather than astrocytes in mixed glial cultures. Examination of MIP-2 mRNA expression showed that H/R upregulated MIP-2 gene expression. Taken together, our data suggest that microglial cells are an important source of MIP-2 production and suggest a potential injury mechanism involving brain-derived production of MIP-2 in H/R.
Wang
J Y
JY
Graduate Institute of Life Sciences and Department of Physiology, National Defense Medical Center, Taipei, Taiwan, Republic of China. jywang@ndmctsgh.edu.tw
Shum
A Y
AY
Chao
C C
CC
Kuo
J S
JS
Wang
J Y
JY
D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D054426:Chemokine CXCL2; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics; D004334:Drug Administration Schedule; D004660:Encephalitis / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D020925:Hypoxia-Ischemia, Brain / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D017628:Microglia / Q000378:metabolism / Q000473:pathology; D009457:Neuroglia / Q000378:metabolism* / Q000473:pathology; D009504:Neutrophils / Q000378:metabolism / Q000473:pathology; D010100:Oxygen / Q000378:metabolism / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013997:Time Factors
D054426:Chemokine CXCL2; D018925:Chemokines; C404915:Cxcl2 protein, mouse; D012333:RNA, Messenger; D010100:Oxygen