Co-ordinated and cellular specific induction of the components of the IGF/IGFBP axis in the rat brain following hypoxic–ischemic injury

Autor: Naomi L. Baker, Arjan Scheepens, Erica J. Beilharz, Vincenzo C. Russo, Chris E. Williams, Bronwyn Connor, Ernest Sirimanne, George A. Werther, Gary Butler, Peter D. Gluckman, Mike Dragunow
Rok vydání: 1998
Předmět:
medicine.medical_specialty
medicine.medical_treatment
Ischemia
In situ hybridization
Biology
Brain Ischemia
Receptor
IGF Type 1
Cellular and Molecular Neuroscience
Insulin-like growth factor
Insulin-Like Growth Factor II
Internal medicine
Glial Fibrillary Acidic Protein
medicine
Animals
RNA
Messenger
Northern blot
Insulin-Like Growth Factor I
Rats
Wistar
Hypoxia
Brain
Molecular Biology
In Situ Hybridization
Brain Chemistry
Cerebral Cortex
Neurons
Microglia
Growth factor
Antibodies
Monoclonal
medicine.disease
Rats
Insulin-Like Growth Factor Binding Proteins
Insulin-Like Growth Factor Binding Protein 2
Insulin-Like Growth Factor Binding Protein 3
Endocrinology
medicine.anatomical_structure
Gene Expression Regulation
Choroid plexus
Insulin-Like Growth Factor Binding Protein 5
Ependyma
Insulin-Like Growth Factor Binding Protein 6
Neuroglia
Zdroj: Molecular Brain Research. 59:119-134
ISSN: 0169-328X
DOI: 10.1016/s0169-328x(98)00122-3
Popis: Insulin-like growth factor 1 (IGF-1) is induced after hypoxic-ischemic (HI) brain injury, and therapeutic studies suggest that IGF-1 may restrict delayed neuronal and glial cell loss. We have used a well-characterised rat model of HI injury to extend our understanding of the modes of action of the IGF system after injury. The induction of the IGF system by injury was examined by in situ hybridization, immunohistochemistry, Northern blot analysis, RNase protection assay and reverse transcriptase-polymerase chain reaction (RT-PCR). IGF-1 accumulated in blood vessels of the damaged hemisphere within 5 h after a severe injury. By 3 days, IGF-1 mRNA was expressed by reactive microglia in regions of delayed neuronal death, and immunoreactive IGF-1 was associated with these microglia and reactive astrocytes juxtaposed to surviving neurones surrounding the infarct. Total IGF-1 receptor mRNA was unchanged by the injury. IGFBP-2 mRNA was strongly induced in reactive astrocytes throughout the injured hemisphere, and IGFBP-3 and IGFBP-5 mRNA were moderately induced in reactive microglia and neurones of the injured hippocampus, respectively. IGFBP-6 mRNA was induced in the damaged hemisphere by 3 days and increased protein was seen on the choroid plexus, ependyma and reactive glia. In contrast, insulin II was not induced. These results indicate cell type-specific expression for IGF-1, IGFBP-2,3,5 and 6 after injury. Our findings suggest that the IGF-1 produced by microglia after injury is transferred to perineuronal reactive astrocytes expressing IGFBP-2. Thus, modulation of IGF-1 action by IGFBP-2 might represent a key mechanism that restricts neuronal cell loss following HI brain injury.
Databáze: OpenAIRE
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