Document Detail


Measurement of amino acid levels in the vitreous humor of rats after chronic intraocular pressure elevation or optic nerve transection.
MedLine Citation:
PMID:  12362078     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: To investigate whether the levels of free amino acids and protein in the vitreous of rat eyes are altered with chronic intraocular pressure (IOP) elevation or after optic nerve transection. MATERIALS AND METHODS: The concentrations of 20 amino acids in the vitreous humor were measured by high-performance liquid chromatography in both eyes of 41 rats with unilateral IOP elevation induced by translimbal photocoagulation. Eyes were studied 1 day and 1, 2, 4, and 9 weeks after initial IOP elevation. The same amino acids were measured in 41 rats 1 day and 2, 4, and 9 weeks after unilateral transection of the orbital optic nerve. The intravitreal protein level was assayed in additional 22 rats with IOP elevation and 12 rats after nerve transection. Two masked observers evaluated the amount of optic nerve damage with a semiquantitative, light-microscopic technique. RESULTS: In rats with experimental glaucoma, amino acid concentrations were unchanged 1 day after treatment. At 1 week, 4 of 20 amino acids (aspartate, proline, alanine, and lysine) were higher than in control eyes ( < or = 0.01), but this difference was nonsignificant after Bonferroni correction for multiple simultaneous amino acid comparisons (none achieved < 0.0025). No amino acid was significantly different from control in the nerve transection groups (all > 0.05). Vitreous protein level was significantly higher in glaucomatous eyes than their paired controls at 1 day ( < 0.0001) and 1 week ( < 0.002). One day and 1 week after optic nerve transection, vitreal proteins were significantly elevated compared with control eyes from untreated animals ( < 0.0020 and < 0.0022, respectively), though not compared with their fellow eyes ( = 0.25 and 0.10). CONCLUSION: Chronic experimental glaucoma and transection of the optic nerve increase the amount of protein in the rat vitreous above control levels. In the vitreous of rats with experimental glaucoma, a number of free amino acids were transiently elevated to a modest degree, but no significant difference in vitreous glutamate concentration was detected ( > 0.01).
Authors:
Hana Levkovitch-Verbin; Keith R G Martin; Harry A Quigley; Lisa A Baumrind; Mary Ellen Pease; Danielle Valenta
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of glaucoma     Volume:  11     ISSN:  1057-0829     ISO Abbreviation:  J. Glaucoma     Publication Date:  2002 Oct 
Date Detail:
Created Date:  2002-10-03     Completed Date:  2002-12-03     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  9300903     Medline TA:  J Glaucoma     Country:  United States    
Other Details:
Languages:  eng     Pagination:  396-405     Citation Subset:  IM    
Affiliation:
Glaucoma Service, Wilmer Ophthalmological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acids / metabolism*
Animals
Chromatography, High Pressure Liquid
Intraocular Pressure*
Ocular Hypertension / metabolism*
Optic Nerve / pathology
Optic Nerve Injuries / metabolism*,  pathology
Rats
Rats, Wistar
Retinal Ganglion Cells / pathology
Vitreous Body / metabolism*
Grant Support
ID/Acronym/Agency:
EY 01765/EY/NEI NIH HHS; EY 02120/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Amino Acids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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