Oxygen-induced retinopathy in the rat model |
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Authors: | Benedetto Ricci |
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Institution: | (1) Department of Ophthalmology, Catholic University of the Sacred Heart, Policlinico Universitario, A. Gemelli, Largo F. Vito, I - 00168 Rome, Italy;(2) Dept. of Ophthalmology, Catholic University of the Sacred Heart, Largo F. Vito, I - 00168 Rome, Italy |
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Abstract: | Identification of a suitable animal model is essential for the continued study of retinopathy of prematurity (ROP). Since
1984 we have used the newborn rat for the study of oxygen-induced retinopathy (OIR). The rat retina is highly immature at
birth. Like those of humans, the retinal vessels arise from mesenchymal precursors, but contrary to that which occurs in humans,
canalization of the rats inner retinal vessels is not related to the presence of cystoid spaces. In addition, only immature
Stage I photoreceptors are present around the optic disk at birth. This extreme immaturity makes the rat retina highly susceptible
to direct damage from oxygen.
Oxygen-induced retinopathy can be produced by exposing the newborn rat to 80% oxygen for the first 7–10 days of life. We have
demonstrated that OIR does not develop when oxygen is administered under conditions of moderate hyperbarism (+ 1.8 atm). It
is possible that hyperbarism exerts a protective effect on the immature retinal vessels by inducing a vasoconstrictive response
which reduces the amount of oxygen transported from the choroid to the inner retina during hypoxia. I recently hypothesized
that this vasoconstriction might also affect the ciliary body, thus reducing the quantity of aqueous produced, and we are
currently studying the relationship between development of the immature retinal vessels in the rat and production and drainage
of the aqueous. The question we are attempting to answer is whether a condition of relatively increased intraocular pressure
is capable of promoting the development of OIR. |
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Keywords: | retinopathy of prematurity newborn rat oxygen oxygen-induced retinopathy intraocular pressure |
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