title: Losses of NG2 and NeuN immunoreactivity but not astrocytic markers during early reperfusion following severe focal cerebral ischemia.
abstract: The ability of glia to recover essential functions following a period of focal cerebral ischemia is likely to be one important factor influencing the severity of tissue damage that subsequently develops. In this study, we have compared changes in immunoreactivity of markers specific for astrocytes, NG2-positive glia and neurons in tissue subregions during early reperfusion following 3 h of middle cerebral artery occlusion to provide insights into possible differential susceptibility of these cell populations. Under the conditions used, infarction ultimately encompasses most of the perfusion territory of the occluded artery. Nonetheless, alterations in immunoreactivity during the first 3 h of recirculation were restricted to brain regions that had been subjected to severe ischemia. In the striatum, cellular immunoreactivity for NG2 and neuronal markers, NeuN and microtubule-associated protein 2, was greatly reduced by 1 h of reperfusion and declined further at 3 h. NG2 labeling of blood vessels in the striatum appeared post-ischemically, mimicking expression of this protein during development. Less severe changes were seen in the neuronal markers in overlying cerebral cortex. In contrast to the losses of other cellular proteins, immunoreactivity for the astrocytic marker, glial fibrillary acidic protein, was preserved in all tissue that had been subjected to severe ischemia and labeling of another astrocytic protein, glutamine synthetase, was increased by 3 h of reperfusion. These findings provide the first evidence of marked sensitivity of NG2-immunoreactivity to severe ischemia and suggest a greater initial resistance of astrocytes compared with neurons and NG2-positive glia to ischemia-reperfusion damage.
authors.affiliation: Centre for Neuroscience and Department of Medical Biochemistry, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia. diane.lee@flinders.edu.au
authors.forename: Diane R
authors.initials: DR
authors.lastname: Lee
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Helps
authors.forename: Ian L
authors.initials: IL
authors.lastname: Gibbins
authors.forename: Michael
authors.initials: M
authors.lastname: Nilsson
authors.forename: Neil R
authors.initials: NR
authors.lastname: Sims
mesh_terms: D000818:Animals; D000941:Antigens / Q000378:metabolism*; D001253:Astrocytes / Q000378:metabolism*; D001562:Benzimidazoles / Q000378:metabolism; D015415:Biomarkers; D001786:Blood Glucose; D001794:Blood Pressure; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002545:Brain Ischemia / Q000378:metabolism*; D004734:Energy Metabolism; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D010751:Phosphopyruvate Hydratase / Q000378:metabolism*; D011509:Proteoglycans / Q000378:metabolism*; D011806:Quinolinium Compounds / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism*; D013844:Thiazoles / Q000378:metabolism; D000099216:Chondroitin Sulfate Proteoglycan 4
chemical_list: D000941:Antigens; D001562:Benzimidazoles; D015415:Biomarkers; D001786:Blood Glucose; D005904:Glial Fibrillary Acidic Protein; D005974:Glutamate-Ammonia Ligase; D008869:Microtubule-Associated Proteins; D010751:Phosphopyruvate Hydratase; D011509:Proteoglycans; D011806:Quinolinium Compounds; D013844:Thiazoles; D000099216:Chondroitin Sulfate Proteoglycan 4; C447680:hoechst 32258; C075295:1,1'-(4,4,7,7-tetramethyl-4,7-diazaundecamethylene)bis-4-(3-methyl-2,3-dihydro(benzo-1,3-thiazole)-2-methylidene)quinolinium