PURPOSE. The purpose of this study was to determine the effect of an angiot
ensin converting ena me inhibitor, captopril, on oxygen-induced retinopathy
(OIR) in the mouse. Endothelin-1 (ET-1) expression is assessed in a mouse
model of OIR.
METHODS. OIR was produced in C57BL6 mice. Captopril (0.5mg/kg/d SC) was giv
en from P7 (post natal day 7) for 5 days. Retinopathy was assessed by a ret
inal scoring system and by quantification of extra retinal neovascular nucl
ei on retinal sections at P17 to P20. The expression of ET-1 was determined
using a reverse transcriptase polymerase chain reaction.
RESULTS. Pups treated with captopril during hyperoxia had a lower median re
tinopathy score of 4.5 (25th, 75th quartile: 3, 6.4) compared with animals
exposed to hyperoxia alone with median score 9.5 (25th, 75th quartile: 7.1,
10.4; P < 0.001). The pups treated with captopril during hyperoxia had sig
nificant reduction in number of nuclei extending beyond the inner limiting
membrane (15.8 +/- 16.7, mean +/- SD) when compared with the animals expose
d to hyperoxia only (50.4 +/- 28.0; P < 0.01). ET-1 expression in the retin
a increased 4.1-fold from P7 to P12 and a 1.9-fold increase from P12 to P17
. Overall, there was an 8-fold increase in ET-1 expression from P7 to P17.
Hyperoxia increased ET-1 expression by 2.1-fold at P12 over room air-reared
animals. At P17, there was a 2.9-fold increase in retinal ET-1 expression
when compared with room air. At P17, there was a 6.2-fold suppression in ET
-1 expression in captopril-treated animals when compared with the oxygen on
ly-treated animals.
CONCLUSIONS. Captopril reduces retinal neovascularization in a mouse model
of oxygen-induced retinopathy. ET-1 expression is increased from P7 to P17,
altered by hyperoxic exposure and relative hypoxic recovery and modulated
by captopril in a mouse model of OIR.