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PURPOSE: To investigate global protein expression profiles in the retinas of normal and glucocorticoid-induced ocular hypertensive rats by proteomic analysis. METHODS: Ocular hypertension was induced by topical application of dexamethasone (DEX) for 4 weeks. Age-matched untreated rats served as controls. Intraocular pressure (IOP) was monitored by an electronic tonometer. Retinal protein expression profiling was carried out by two-dimensional fluorescence difference gel electrophoresis (2-D DIGE). Proteins were identified by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. RESULTS: In DEX-treated rats, average IOP was elevated significantly compared with controls. With DEX treatment, levels of four proteins were altered, as revealed by 2-D DIGE and MALDI-TOF mass spectrometry: apolipoprotein A1 (apoA1), a lipid-binding protein, upregulated 1.9-fold, P < 0.05; alpha A crystallin (CRYAA), a molecular chaperone, downregulated 2.7-fold, P < 0.01; superoxide dismutase 1 (SOD1), an antioxidant enzyme, downregulated 2.3-fold, P < 0.05; and triosephosphate isomerase 1 (TPI1), a glycolytic enzyme, downregulated 2.3-fold, P < 0.01. CONCLUSIONS: Downregulation of CRYAA, SOD1, and TPI1, observed here after a short period of DEX-induced ocular hypertension, may be involved in the onset of neural damage in steroid-induced glaucoma.
Dr. N. Miyara, Department of Ophthalmology and Visual Sciences, School of Medicine, University of the Ryukyus, Okinawa, Japan. kariya@med.u-ryukyu.ac.jp
9.4.1 Steroid-induced glaucoma (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
3.12 Proteomics (Part of: 3 Laboratory methods)