TY - JOUR
T1 - Irradiation induces regionally specific alterations in pro-inflammatory environments in rat brain
AU - Lee, Won Hee
AU - Sonntag, William E.
AU - Mitschelen, Matthew
AU - Yan, Han
AU - Lee, Yong Woo
N1 - Funding Information:
The editorial assistance of MaryAnn Sonntag in preparation of the manuscript is greatly appreciated. The project described was supported by Grant Number R01NS056218 from the National Institute of Neurological Disorders and Stroke.
PY - 2010/2
Y1 - 2010/2
N2 - Purpose: Pro-inflammatory environments in the brain have been implicated in the onset and progression of neurological disorders. In the present study, we investigate the hypothesis that brain irradiation induces regionally specific alterations in cytokine gene and protein expression. Materials and methods: Four month old F344×BN rats received either whole brain irradiation with a single dose of 10 Gy γ-rays or sham-irradiation, and were maintained for 4, 8, and 24h following irradiation. The mRNA and protein expression levels of pro-inflammatory mediators were analysed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining. To elucidate the molecular mechanisms of irradiation-induced brain inflammation, effects of irradiation on the DNA-binding activity of pro-inflammatory transcription factors were also examined. Results: A significant and marked up-regulation of mRNA and protein expression of pro-inflammatory mediators, including tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1), was observed in hippocampal and cortical regions isolated from irradiated brain. Cytokine expression was regionally specific since TNF-α levels were significantly elevated in cortex compared to hippocampus (57 greater) and IL-1β levels were elevated in hippocampus compared to cortical samples (126 greater). Increases in cytokine levels also were observed after irradiation of mouse BV-2 microglial cells. A series of electrophoretic mobility shift assays (EMSA) demonstrated that irradiation significantly increased activation of activator protein-1 (AP-1), nuclear factor-κB (NF-κB), and cAMP response element-binding protein (CREB). Conclusion: The present study demonstrated that whole brain irradiation induces regionally specific pro-inflammatory environments through activation of AP-1, NF-κB, and CREB and overexpression of TNF-α, IL-1β, and MCP-1 in rat brain and may contribute to unique pathways for the radiation-induced impairments in tissue function.
AB - Purpose: Pro-inflammatory environments in the brain have been implicated in the onset and progression of neurological disorders. In the present study, we investigate the hypothesis that brain irradiation induces regionally specific alterations in cytokine gene and protein expression. Materials and methods: Four month old F344×BN rats received either whole brain irradiation with a single dose of 10 Gy γ-rays or sham-irradiation, and were maintained for 4, 8, and 24h following irradiation. The mRNA and protein expression levels of pro-inflammatory mediators were analysed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunofluorescence staining. To elucidate the molecular mechanisms of irradiation-induced brain inflammation, effects of irradiation on the DNA-binding activity of pro-inflammatory transcription factors were also examined. Results: A significant and marked up-regulation of mRNA and protein expression of pro-inflammatory mediators, including tumour necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1), was observed in hippocampal and cortical regions isolated from irradiated brain. Cytokine expression was regionally specific since TNF-α levels were significantly elevated in cortex compared to hippocampus (57 greater) and IL-1β levels were elevated in hippocampus compared to cortical samples (126 greater). Increases in cytokine levels also were observed after irradiation of mouse BV-2 microglial cells. A series of electrophoretic mobility shift assays (EMSA) demonstrated that irradiation significantly increased activation of activator protein-1 (AP-1), nuclear factor-κB (NF-κB), and cAMP response element-binding protein (CREB). Conclusion: The present study demonstrated that whole brain irradiation induces regionally specific pro-inflammatory environments through activation of AP-1, NF-κB, and CREB and overexpression of TNF-α, IL-1β, and MCP-1 in rat brain and may contribute to unique pathways for the radiation-induced impairments in tissue function.
KW - AP-1
KW - Brain inflammation
KW - CREB
KW - Cytokines
KW - NF-κB
KW - Radiation
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U2 - 10.3109/09553000903419346
DO - 10.3109/09553000903419346
M3 - Article
C2 - 20148699
AN - SCOPUS:77249171256
SN - 0955-3002
VL - 86
SP - 132
EP - 144
JO - International Journal of Radiation Biology
JF - International Journal of Radiation Biology
IS - 2
ER -