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PURPOSE: To investigate global protein expression profiles in the trabecular meshwork (TM) of normal and glucocorticoid-induced ocular hypertensive rat eyes by proteomic analysis, which has not yet been conducted to date. Materials and METHODS: A rat ocular hypertension model was produced by topical application of dexamethasone (DEX) for four weeks. Age-matched untreated rats served as controls. Intraocular pressure (IOP) was monitored by an electronic tonometer. TM protein expression profiling and protein identification was carried out by a two-dimensional fluorescence differential gel electrophoresis (2-D DIGE) system and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, respectively. RESULTS: In DEX-treated rats, average IOP was elevated significantly, as compared with controls. By the DEX treatment, 14 TM protein spots were up- or downregulated consistently in 2-D DIGE analyses. Proteins exhibiting more than two-fold statistically significant change were identified by MALDI-TOF mass spectrometry. αA-Crystallin and βA(3)-crystallin were upregulated, while the C-propeptides of type I collagen were downregulated. CONCLUSION: Relatively short-term glucocorticoid application induced alteration in the expression of a number of proteins, including downregulation of type I collagen C-propeptides. This could reflect impaired collagen turnover in the TM of glucocorticoid-treated eyes.
Dr. M. Shinzato, Department of Ophthalmology and Visual Sciences, School of Medicine, University of the Ryukyus, Okinawa, Japan
3.12 Proteomics (Part of: 3 Laboratory methods)
2.5.1 Trabecular meshwork (Part of: 2 Anatomical structures in glaucoma > 2.5 Meshwork)
5.1 Rodent (Part of: 5 Experimental glaucoma; animal models)
9.4.1 Steroid-induced glaucoma (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)