title: Transient inflammation in neurogenic regions after irradiation of the developing brain.
abstract: We characterized the inflammatory response after a single dose of 8 Gy to the brains of postnatal day 9 rats. Affymetrix gene chips revealed activation of multiple inflammatory mechanisms in the acute phase, 6 h after irradiation. In the subacute phase, 7 days after irradiation, genes related to neurogenesis and cell cycle were down-regulated, but glial fibrillary acidic protein (GFAP) was up-regulated. The concentrations of 14 different cytokines and chemokines were measured using a microsphere-based xMAP technology. CCL2, Gro/KC and IL-1alpha were the most strongly up-regulated 6 h after irradiation. CCL2 was expressed in astrocytes and microglia in the dentate gyrus and the subventricular zone (SVZ). Hypertrophy, but not hyperplasia, of astrocytes was demonstrated 7 days after irradiation. In summary, we found transient activation of multiple inflammatory mechanisms in the acute phase (6 h) after irradiation and activation of astrocytes in the subacute phase (7 days) after irradiation. It remains to be elucidated whether these transient changes are involved in the persistent effects of radiation observed on neurogenesis and cognition in rodents.
authors.affiliation: Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Marie
authors.initials: M
authors.lastname: Kalm
authors.forename: Aya
authors.initials: A
authors.lastname: Fukuda
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Fukuda
authors.forename: Annika
authors.initials: A
authors.lastname: Ohrfelt
authors.forename: Birgitta
authors.initials: B
authors.lastname: Lannering
authors.forename: Thomas
authors.initials: T
authors.lastname: Björk-Eriksson
authors.forename: Kaj
authors.initials: K
authors.lastname: Blennow
authors.forename: Ildikó
authors.initials: I
authors.lastname: Márky
authors.forename: Klas
authors.initials: K
authors.lastname: Blomgren
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D001253:Astrocytes / Q000378:metabolism / Q000528:radiation effects; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000254:growth & development / Q000378:metabolism / Q000473:pathology* / Q000528:radiation effects*; D018932:Chemokine CCL2 / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005911:Gliosis / Q000473:pathology; D007118:Immunoassay; D007150:Immunohistochemistry; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D017628:Microglia / Q000378:metabolism / Q000528:radiation effects; D055495:Neurogenesis; D020411:Oligonucleotide Array Sequence Analysis; D018384:Oxidative Stress / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D015415:Biomarkers; D018932:Chemokine CCL2