Inner retinal oxygen metabolism in the 50/10 oxygen-induced retinopathy model.

Brian T. Soetikno,Patryk Purta,Ronil Shah,Hao F. Zhang,Ji Yi,Amani A. Fawzi,Wenzhong Liu

doi:10.1038/srep16752

Brian T. Soetikno, Patryk Purta + Show 5 more

Open Access

https://doi.org/10.1038/srep16752

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Journal: Scientific Reports	Publication Date: Nov 18, 2015
Citations: 33	License type: CC BY 4.0

Affiliation: Northwestern University

Abstract

Retinopathy of prematurity (ROP) represents a major cause of childhood vision loss worldwide. The 50/10 oxygen-induced retinopathy (OIR) model mimics the findings of ROP, including peripheral vascular attenuation and neovascularization. The oxygen metabolism of the inner retina has not been previously explored in this model. Using visible-light optical coherence tomography (vis-OCT), we measured the oxygen saturation of hemoglobin and blood flow within inner retinal vessels, enabling us to compute the inner retinal oxygen delivery (irDO2) and metabolic rate of oxygen (irMRO2). We compared these measurements between age-matched room-air controls and rats with 50/10 OIR on postnatal day 18. To account for a 61% decrease in the irDO2 in the OIR group, we found an overall statistically significant decrease in retinal vascular density affecting the superficial and deep retinal vascular capillary networks in rats with OIR compared to controls. Furthermore, matching the reduced irDO2, we found a 59% decrease in irMRO2, which we correlated with a statistically significant reduction in retinal thickness in the OIR group, suggesting that the decreased irMRO2 was due to decreased neuronal oxygen utilization. By exploring these biological and metabolic changes in great detail, our study provides an improved understanding of the pathophysiology of OIR model.

Highlights

24 hours, beginning at birth and continuing until postnatal day 14 (P14)[8]
Oxygen is thought to be a key player in the pathogenesis of OIR, Retinopathy of prematurity (ROP), and other proliferative retinopathies, oxygen metabolism has not been well studied in these diseases
Because hemoglobin is highly absorbing within the visible-light spectral range, shadows were cast underneath the inner retinal blood vessels. Taking advantage of this light attenuation, we selected a 3-D slab of retina below the inner retinal vessels and performed maximum amplitude projection (MAP), along the depth dimension, to obtain an en face image of the inner retinal vessel shadows

Summary

Introduction

24 hours, beginning at birth and continuing until postnatal day 14 (P14)[8]. Upon return to room air at. Oxygen is thought to be a key player in the pathogenesis of OIR, ROP, and other proliferative retinopathies (e.g. diabetic retinopathy), oxygen metabolism has not been well studied in these diseases In part, this may be due to the absence of imaging technologies than can quantify the inner retinal metabolic rate of oxygen (irMRO2) and inner retinal delivery rate of oxygen (irDO2), functional markers which fully describe the tissue oxygen consumption and oxygen delivery, respectively. This may be due to the absence of imaging technologies than can quantify the inner retinal metabolic rate of oxygen (irMRO2) and inner retinal delivery rate of oxygen (irDO2), functional markers which fully describe the tissue oxygen consumption and oxygen delivery, respectively Other markers, such as the oxygen saturation of hemoglobin (sO2), total retinal blood flow (FTotal), and oxygen extraction fraction (OEF), contribute to the irMRO2 and irDO2; studying any of these measurements in isolation warrants caution because it provides a limited picture of oxygen metabolism.

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