Increased H2O2, vascular endothelial growth factor and receptors in the retina of the BBZ/WOR diabetic rat

E. Ann Ellis, Dennis L. Guberski, Marta Somogyi-Mann, Maria B. Grant

Research output: Contribution to journalArticle

135 Scopus citations

Abstract

Hyperglycemia in diabetes induces increased levels of hydrogen peroxide (H2O2), a reactive oxygen species generated by reduced nicotinamide adenine dinucleotide (NADH) oxidase. Nontoxic levels of H2O2 increase endothelial cell permeability. Using a model of non-insulin-dependent diabetes, the BBZ/Wor rat, we investigated retinal levels of H2O2, vascular endothelial growth factor (VEGF) and its receptors, VEGF-R1 and VEGF-R2 by transmission electron microscopy at sites of the blood-retinal barrier (BRB). H2O2 localization was done by the cerium NADH oxidase method, and extravasation of endogenous serum albumin was used to document disruption of the BRB. Higher levels of H2O2 were detected in blood vessels of diabetic (78.7 ± 4.84%) as compared with vessels from nondiabetic rats (39.0 ± 4.47%). VEGF immunoreactivity was statistically higher in the inner BRB (24.67 ± 0.33 colloidal gold particles/63 μm2 vs. 21.52 ± 0.43 colloidal gold particles/63 μm2, p = .0001) and outer BRB (42.56 ± 0.45 colloidal gold particles/63 μm2 vs. 15.51 ± 0.51 colloidal gold particles/63 μm2, p = .0001) of diabetic rats as compared with age matched nondiabetic control rats. VEGF-R1 immunoreactivity was significantly higher in diabetic retinas in both the inner BRB (21.66 ± 0.75 colloidal gold particles/63 μm2 vs. 12.69 ± 0.61 colloidal gold particles/63 μm2, p = .0001) and outer BRB (22.76 ± 2.36 colloidal gold particles/63 μm2 vs. 8.53 ± 2.67 colloidal gold particles/63 μm2, p = .0013). VEGF-R2 was statistically higher in the inner BRB (8.97 ± 0.57 colloidal gold particles/63 μm2 versus 7.03 ± 0.65 colloidal gold particles/63 μm2, p = .0419) but not in the outer BRB (29.42 ± 1.25 colloidal gold particles/63 μm2 vs. 28.07 ± 1.42 colloidal gold particles/63 μm2, p = .4889). H2O2 levels correlated with increased VEGF (correlation coefficient = 0.82, p = .001) in this model of nonproliferative diabetic retinopathy. These results support that hyperglycemia is one factor that induces retinal endothelial cells in vivo to increase H2O2 via NADH oxidase and stimulates increases in VEGF resulting in disruption of the BRB. Copyright (C) 2000 Elsevier Science Inc.

Original languageEnglish (US)
Pages (from-to)91-101
Number of pages11
JournalFree Radical Biology and Medicine
Volume28
Issue number1
DOIs
StatePublished - Jan 1 2000

    Fingerprint

Keywords

  • Blood-retinal barrier
  • Diabetes
  • Free radicals
  • HO
  • NADH oxidase
  • Oxidative stress
  • Retinopathy
  • VEGF
  • VEGF receptors

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)

Cite this