Proteomic analysis of rat retina in a steroid-induced ocular hypertension model: potential vulnerability to oxidative stress.
OBJECTIVE
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.
Miyara
Nariko
N
Department of Ophthalmology and Visual Sciences, School of Medicine, University of the Ryukyus, Okinawa, Japan.|Division of Cell Biology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa, 903-0215, Japan.
Shinzato
Manabu
M
Department of Ophthalmology and Visual Sciences, School of Medicine, University of the Ryukyus, Okinawa, Japan.|Division of Cell Biology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa, 903-0215, Japan.
Yamashiro
Yoshito
Y
Division of Cell Biology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa, 903-0215, Japan.
Iwamatsu
Akihiro
A
Protein Research Network, Yokohama, Japan.
Kariya
Ken-Ichi
KI
Division of Cell Biology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Okinawa, 903-0215, Japan. kariya@med.u-ryukyu.ac.jp.
Sawaguchi
Shoichi
S
Department of Ophthalmology and Visual Sciences, School of Medicine, University of the Ryukyus, Okinawa, Japan.
D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism; D003907:Dexamethasone; D004195:Disease Models, Animal; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D005938:Glucocorticoids; D007429:Intraocular Pressure; D009798:Ocular Hypertension / Q000139:chemically induced / Q000378:metabolism*; D018384:Oxidative Stress; D040901:Proteomics; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D014305:Triose-Phosphate Isomerase / Q000378:metabolism; D038202:alpha-Crystallin A Chain / Q000378:metabolism
D016632:Apolipoprotein A-I; D005938:Glucocorticoids; D038202:alpha-Crystallin A Chain; D003907:Dexamethasone; C000606292:Sod1 protein, rat; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D014305:Triose-Phosphate Isomerase