Time course of NADH oxidase, inducible nitric oxide synthase and peroxynitrite in diabetic retinopathy in the BBZ/WOR rat.
This study investigated the time course of NADH oxidase, a source of superoxide in the vascular endothelium, inducible nitric oxide synthase (iNOS), and peroxynitrite (ONOO(-)) in the BBZ/Wor rat, a spontaneous model of noninsulin dependent diabetes (NIDDM). Colloidal gold-labeled immunocytochemical studies of iNOS and nitrotyrosine, a marker for OONO(-), were done on sections of retinas from male BBZ/Wor rats in which NADH oxidase was localized by cerium derived cytochemistry at three time points: pre-diabetes (prior to the onset of hyperglycemia); new onset diabetes (2-6 days after onset of hyperglycemia); and chronic diabetes (4-18 months after onset of hyperglycemia). Control retinas were from age matched non-diabetic BB(DR)/Wor rats. The percentage of blood vessels positive for NADH oxidase increased significantly (P = 0.05) in new onset (64.2 +/- 6.5%) and chronic diabetes (83.2 +/- 11.4%), as compared to pre-diabetes (25.8 +/- 5.6%) and nondiabetic controls (33.6 +/- 15.9%). The percentage of blood vessels positive for iNOS immunoreactivity was significantly higher in new onset diabetic retinas (69.6 +/- 5.88%, P = 0.0001; 8.9 +/- 3.29 colloidal gold particles (cgp) /50 microm(2)) than in chronic diabetic retinas (49.9 +/- 9.75%; 7.9 +/- 5.12 cgp) and both were significantly higher (P = 0.0001) than in prediabetic (3.7 +/- 0.81%; 0.4 +/- 0.56 cgp) and nondiabetic control retinas (8.7 +/- 4.66%; 1.2 +/- 1.40 cgp). In new onset diabetes, levels of nitrotyrosine immunoreactivity (60.8 +/- 16.91 cgp) were significantly higher (P = 0.0001) than those in chronic diabetes (29.5 +/- 4.31 cgp); both were significantly higher (P = 0.0001) than those in prediabetic (8.2 +/- 1.70 cgp) and nondiabetic retinas (9.0 +/- 1.87 cgp). There was no cumulative increase in nitrotyrosine in the chronic diabetic retinas as a function of time. In rats with diabetes there was disruption of the inner blood-retinal barrier. These results suggest that iNOS and ONOO(-) may contribute to retinal damage in diabetes from the onset of hyperglycemia in NIDDM.
Ellis
E Ann
EA
Department of Pharmacology and Therapeutics, College of Medicine, Gainesville, Florida 32610, USA.
Guberski
Dennis L
DL
Hutson
Brenda
B
Grant
Maria B
MB
D000818:Animals; D003930:Diabetic Retinopathy / Q000378:metabolism*; D007150:Immunohistochemistry; D007700:Kinetics; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D030421:Peroxynitrous Acid / Q000378:metabolism*; D051381:Rats
D009097:Multienzyme Complexes; D030421:Peroxynitrous Acid; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases