Susceptibility of streptozotocin-induced diabetic rat retinal function and ocular blood flow to acute intraocular pressure challenge
AuthorWong, Vickie H. Y.; Vingrys, Algis J.; Jobling, Andrew I.; Bui, Bang V.
Source TitleInvestigative Ophthalmology & Visual Science
PublisherAssociation for Research in Vision and Ophthalmology (ARVO)
University of Melbourne Author/sWong, Vickie; Vingrys, Algis; Jobling, Andrew; Bui, Bang; Cole, Barry
AffiliationDepartment of Optometry and Vision Sciences
Optometry and Vision Sciences
Document TypeJournal Article
CitationsWong, V. H. Y., Vingrys, A. J., Jobling, A. I. & Bui, B. V. (2013). Susceptibility of streptozotocin-induced diabetic rat retinal function and ocular blood flow to acute intraocular pressure challenge. Investigative Ophthalmology & Visual Science, 54(3), 2133-2141.
Access StatusThis item is currently not available from this repository
NHMRC Grant codeNHMRC/566570
Copyright 2013 The Association for Research in Vision and Ophthalmology, Inc.
The research outputs in this collection have been funded in whole or in part by the National Health and Medical Research Council (NHMRC)
Purpose: To consider the hypothesis that streptozotocin (STZ)-induced hyperglycemia renders rat retinal function and ocular blood flow more susceptible to acute IOP challenge. Methods: Retinal function (electroretinogram [ERG]) was measured during acute IOP challenge (10–100 mm Hg, increments of 5 mm Hg, 3 minutes per step, vitreal cannulation) in adult Long-Evans rats (6 weeks old; citrate: n = 6, STZ: n = 10) 4 weeks after citrate buffer or STZ (65 mg/kg, blood glucose >15 mM) injection. At each IOP, dim and bright flash (−4.56, −1.72 log cd.s.m−2) ERG responses were recorded to measure inner retinal and ON-bipolar cell function, respectively. Ocular blood flow (laser Doppler flowmetry; citrate: n = 6, STZ: n = 10) was also measured during acute IOP challenge. Retinas were isolated for quantitative PCR analysis of nitric oxide synthase mRNA expression (endothelial, eNos; inducible, iNos; neuronal, nNos). Results: STZ-induced diabetes increased the susceptibility of inner retinal (IOP at 50% response, 60.1, CI: 57.0–62.0 mm Hg versus citrate: 67.5, CI: 62.1–72.4 mm Hg) and ON-bipolar cell function (STZ: 60.3, CI: 58.0–62.8 mm Hg versus citrate: 65.1, CI: 61.9–68.6 mm Hg) and ocular blood flow (43.9, CI: 40.8–46.8 versus citrate: 53.4, CI: 50.7–56.1 mm Hg) to IOP challenge. Citrate eyes showed elevated eNos mRNA (+49.7%) after IOP stress, an effect not found in STZ-diabetic eyes (−5.7%, P < 0.03). No difference was observed for iNos or nNos (P > 0.05) following IOP elevation. Conclusions: STZ-induced diabetes increased functional susceptibility during acute IOP challenge. This functional vulnerability is associated with a reduced capacity for diabetic eyes to upregulate eNos expression and to autoregulate blood flow in response to stress.
Keywordsretinal function; ocular blood flow; intraocular pressure
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