Dynamic changes in reactive oxygen species and antioxidant levels in retinas in experimental glaucoma.
We investigated the balance of free radicals in retinas at various time points after chronically elevating intraocular pressures in rats. The left eyes of female Wistar rats were divided into five intraocular pressure elevation (IOPE) subgroups after cauterization of three episcleral veins (1 day, 3 days, 1 week, 3 weeks, and 5 weeks) and time-related sham controls. Chemiluminescence levels were examined in isolated retinas. The nitroblue tetrazolium (NBT) incubation method was also performed to confirm the superoxide expression. The activities of antioxidant enzymes and lipid peroxides in isolated retinas were detected by spectrophotometry. In the IOPE group, the intraocular pressure after cauterization was around 22-30 mm Hg; chemiluminescence levels of isolated retinas were significantly elevated on day 3 and week 1; there were more NBT-positive retinal ganglion cells on day 1 and day 3; lipid peroxidation also increased significantly from day 1 and came back to the baseline on week 5; the activities of superoxide dismutases and catalase rose on week 1. Intraocular pressure elevation was shown to change the free radical balance. We suggest that free radicals and their oxidative stresses may play a role in the early stage of glaucoma in causing retinal ganglion cell death in our rat model.
Department of Ophthalmology, General Hsin-Chu Hospital, Hsin-Chu, Taiwan.
Mei-Lan
ML
Ko
Pai-Huei
PH
Peng
Ming-Chieh
MC
Ma
Robert
R
Ritch
Chau-Fong
CF
Chen
D000818:Animals; D000975:Antioxidants / Q000032:analysis / Q000378:metabolism*; D017209:Apoptosis / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D005901:Glaucoma / Q000378:metabolism / Q000473:pathology*; D007091:Image Processing, Computer-Assisted; D007429:Intraocular Pressure; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000032:analysis / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000378:metabolism / Q000473:pathology*; D012165:Retinal Ganglion Cells / Q000378:metabolism / Q000473:pathology; D013053:Spectrophotometry; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000032:analysis / Q000378:metabolism
D000975:Antioxidants; D017382:Reactive Oxygen Species; D013481:Superoxides; D013482:Superoxide Dismutase