Effects of chronic mild hyperoxia on retinal and choroidal blood flow and retinal function in the DBA/2J mouse model of glaucoma.

Abstract

PurposeTo test the hypothesis that mild chronic hyperoxia treatment would improve retinal function despite a progressive decline in ocular blood flow in the DBA/2J mouse model of glaucoma.Materials and methodsDBA/2J mice were treated with chronic mild hyperoxia (30% O2) beginning at 4.5 months of age or were untreated by giving normal room air. Retinal and choroidal blood flow (RBF and ChBF, respectively) were measured at 4, 6, and 9 months of age by MRI. Blood flow was additionally measured under hypercapnia challenge (5% CO2 inhalation) to assess vascular reactivity. Intraocular pressure (IOP) was measured using a rebound tonometer at the same time points. Scotopic flash electroretinograms (ERGs) were recorded at 9 months of age.ResultsBoth ChBF and RBF were reduced and significantly affected by age (p 0.05). ChBF significantly increased in response to hypercapnia (p 0.05).ConclusionThis study investigated the effects of chronic mild hyperoxia on retinal function and on retinal and choroidal blood flow in a mouse model of glaucoma. Retinal function was improved in the O2-treated mice at late stage, despite a progressive decline of RBF and ChBF with age that was comparable to untreated mice.