Document Detail


Aromatase expression and cell proliferation following injury of the adult zebra finch hippocampus.
MedLine Citation:
PMID:  17823932     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Estrogens can be neuroprotective following traumatic brain injury. Immediately after trauma to the zebra finch hippocampus, the estrogen-synthetic enzyme aromatase is rapidly upregulated in astrocytes and radial glia around the lesion site. Brain injury also induces high levels of cell proliferation. Estrogens promote neuronal differentiation, migration, and survival naturally in the avian brain. We suspect that glia are a source of estrogens promoting cell proliferation after neural injury. To explore this hypothesis, we examined the spatial and temporal relationship between glial aromatase expression and cell proliferation after neural injury in adult female zebra finches. Birds were ovariectomized and given a blank implant or one filled with estradiol; some birds were also administered an aromatase inhibitor or vehicle. All birds received penetrating injuries to the right hippocampus. Twenty-four hours after lesioning, birds were injected once with BrdU to label mitotically active cells and euthanized 2 h, 24 h, or 7 days later. The brains were processed for double-label BrdU and aromatase immunocytochemistry. Injury-induced glial aromatase expression was unaffected by survival time and aromatase inhibition. BrdU labeling was significantly reduced at 24 h by ovariectomy and by aromatase inhibition; effects were partially reversed by E2 replacement. Irrespective of ovariectomy, the densities of aromatase immunoreactive astrocytes and BrdU-labeled cells at known distances from the lesion site were highly correlated. These data suggest that injury-induced glial aromatization may influence the reorganization of injured tissue by providing a rich estrogenic environment available to influence cellular incorporation.
Authors:
R Scott Peterson; Gowry Fernando; Lainy Day; Timothy A Allen; Jeanette D Chapleau; Jenny Menjivar; Barney A Schlinger; Diane W Lee
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Developmental neurobiology     Volume:  67     ISSN:  1932-8451     ISO Abbreviation:  Dev Neurobiol     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2007-11-13     Completed Date:  2008-03-27     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101300215     Medline TA:  Dev Neurobiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1867-78     Citation Subset:  IM    
Affiliation:
Department of Physiological Science, University of California, Los Angeles, CA 90095, USA.
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Animals
Aromatase / metabolism*
Aromatase Inhibitors / pharmacology
Brain Injuries / pathology*,  physiopathology
Bromodeoxyuridine / metabolism
Cell Proliferation* / drug effects
Cerebellum / pathology
Drug Interactions
Estradiol / pharmacology
Estrogens / pharmacology
Fadrozole / pharmacology
Female
Finches
Gene Expression Regulation, Enzymologic / drug effects,  physiology*
Hippocampus / enzymology,  pathology*
Ovariectomy / methods
Time Factors
Grant Support
ID/Acronym/Agency:
HD07228-18/HD/NICHD NIH HHS; MH59730-03/MH/NIMH NIH HHS; MH61994/MH/NIMH NIH HHS; S06 GM063119/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Aromatase Inhibitors; 0/Estrogens; 102676-47-1/Fadrozole; 50-28-2/Estradiol; 59-14-3/Bromodeoxyuridine; EC 1.14.14.1/Aromatase

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