Purchase this article with an account.
Michael Robert Tan, Anthony Felder, Norman P Blair, Mahnaz Shahidi; Alterations in Retinal Oxygen Delivery and Metabolism due to Experimental Retinal Ischemia. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3102.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previous studies have shown long-term retinal morphological changes in experimental models of ischemia/reperfusion injury. The purpose of this study is to investigate short-term alterations in inner retinal oxygen delivery (DO2) and metabolism (MO2) in a rat model of retinal ischemia by ophthalmic vessel occlusion.
In Long Evans rats (N = 9), the ophthalmic vessels of the study eyes were ligated for two hours. Optical section phosphorescence lifetime and blood flow imaging were performed in both eyes within 20 minutes of ligature release. Retinal arterial and venous oxygen tension (PO2A and PO2V), diameter (DA, DV), and venous blood velocity (V) were measured. Total retinal blood flow (F) was calculated from DV and V measurements. DO2 and MO2 were calculated from measurements of F, PO2A and PO2V. Retinal oxygen extraction fraction (OEF) was calculated as MO2 / DO2. Paired t-tests were used to compare measurements between study and fellow eyes.
PO2A and PO2V in study eyes did not recover to values observed in fellow eyes (P ≤ 0.03). In study eyes, DA was lower (P < 0.001), whereas DV was not significantly different than fellow eyes (P = 0.14). Both V and F were lower in study eyes compared to fellow eyes (P ≤ 0.005). DO2 was lower in study eyes (445 ± 282 nL O2/min) compared to fellow eyes (936 ± 298 nL O2/min) (P = 0.004), and MO2 also was lower in study eyes (229 ± 140 nL O2/min) compared to fellow eyes (399 ± 87 nL O2/min) (P = 0.004). OEF in the study eyes (0.61 ± 0.21) was higher compared to fellow eyes (0.44 ± 0.08) (P = 0.05).
Reductions in both DO2 and MO2, coupled with an increase in OEF following a retinal ischemic insult suggest that oxygen delivery recovered more slowly than oxygen metabolism. These findings may have implications in the understanding of retinal ischemia.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only