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In vivo measurement of increased vascular permeability after STZ induction of diabetes in rats by fluorescence angiography using the Micron IV
Author(s) -
Allen C.,
Bates D.
Publication year - 2016
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2016.0468
Subject(s) - retinal , diabetes mellitus , diabetic retinopathy , medicine , streptozotocin , vascular permeability , in vivo , fluorescein angiography , retina , blood–retinal barrier , retinopathy , ophthalmology , endocrinology , biology , microbiology and biotechnology , neuroscience
Purpose Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of blindness. Chemically induced diabetic rodent models mimic some phenotypic changes in DR, but quantitative assessment of increased vascular permeability seen in diabetes usually requires invasive and terminal experiments. The Micron IV provides enhanced sensitivity, resolution, real‐time capture and a non‐invasive platform compared to comparable systems. This study tests the hypothesis that retinal vascular leakage can be assessed in vivo over time, using the Micron IV. Methods FA was carried out in non and diabetic rats on day 0 and 7 using the Micron IV. Animals received a single dose of PBS ( n = 6) or streptozotocin i.p., 50 mg/kg ( n = 6) on day 1 and blood glucose levels were measured on day 4. Angiograms were converted to 8‐bit images in ImageJ and the intensity of sodium fluorescein in an area of the vascular interstitium and the retinal vessel were measured over time. The ratio of interstitial to vascular fluorescence intensities were plotted against time to give rate of increase in intensity per unit time. Results Retinal vascular leak was measured in the same focal position of the retina on day 0 and 7 using the Micron IV. Retinal leak was shown to significantly increase (p < 0.05) in the STZ induced diabetic group (13.3 ± 3.30 × 10 −4 s −1 ) compared to non‐diabetic controls (7.5 ± 3.7 × 10 −4 s −1 ), on day 7. This was supported by fundus images showing increased capillary leakage and the formation of multiple micro‐aneurysms in the retina. Conclusions The Micron IV system provides a standardised, real‐time and non‐invasive platform to measure retinal permeability in a rat model of diabetes. Advanced quantitative assessments such as this could substantially contribute to a better understanding of the pathogenesis of DR and identify potential drugs for treatment.