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Updated: Jun 3, 2026
Oxygen-Induced Retinopathy Model for Ischemic Retinal Diseases in Rodents
Published on: September 16, 2020
Prolyl hydroxylase domain protein 2 (PHD2) mediates oxygen-induced retinopathy in neonatal mice
Li-Juan Duan1, Kotaro Takeda, Guo-Hua Fong
1Center for Vascular Biology, Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030-3501, USA.
Insights
Prolyl hydroxylase domain protein 2 (PHD2) is crucial in oxygen-induced retinopathy. PHD2 deficiency protects retinal microvessels from oxygen damage, suggesting PHD2 as a therapeutic target for preventing retinopathy of prematurity.
Area of Science:
- Ophthalmology
- Neonatology
- Molecular Biology
Background:
- Retinopathy of prematurity (ROP) is a significant cause of childhood blindness.
- Oxygen therapy in preterm infants can lead to ROP, but the underlying mechanisms are not fully understood.
- Hypoxia-inducible factor (HIF) α protein degradation is a potential trigger for ROP.
Purpose of the Study:
- To investigate the role of prolyl hydroxylase domain protein 2 (PHD2) in oxygen-induced retinopathy.
- To determine if PHD2-dependent HIF-α degradation is a key mechanism in ROP development.
Main Methods:
- Utilized a mouse model of oxygen-induced retinopathy.
- Examined the effects of normal and deficient PHD2 expression on retinal microvessels and HIF-α proteins under hyperoxia.
- Assessed retinal vasculature and neoangiogenesis after return to ambient air.
Main Results:
- Normal PHD2 levels led to HIF-α degradation and retinal microvascular loss in mice exposed to oxygen.
- PHD2 deficiency stabilized HIF-α proteins and protected retinal microvessels from oxygen-induced obliteration.
- PHD2-deficient mice showed preserved retinal vasculature with minimal neoangiogenesis after hyperoxia recovery.
Conclusions:
- PHD2 plays a critical role in oxygen-induced retinal microvascular obliteration.
- PHD2-dependent HIF-α degradation is closely associated with ROP development.
- PHD2 inhibition represents a potential therapeutic strategy for preventing ROP.
Abstract:
Retinopathy of prematurity is a major side effect of oxygen therapy for preterm infants, and is a leading cause of blindness in children. To date, it remains unclear whether the initial microvascular obliteration is triggered by degradation of hypoxia inducible factor (HIF) α proteins or by other mechanisms such as oxidative stress. Here we show that prolyl hydroxylase domain protein 2 (PHD2), an enzyme mostly responsible for oxygen-induced degradation of HIF-α proteins, plays a major role in oxygen-induced retinopathy in mice. In neonatal mice expressing normal amounts of PHD2, exposure to 75% oxygen caused significant degradation of retinal HIF-α proteins, accompanied by massive losses of retinal microvessels. PHD2 deficiency significantly stabilized HIF-1α, and to some extent HIF-2α, in neonatal retinal tissues, and protected retinal microvessels from oxygen-induced obliteration. After hyperoxia-treated neonatal mice were returned to ambient room air, retinal vasculature in PHD2-deficient mice remained mostly intact and showed very little neoangiogenesis. These findings demonstrate a close association between PHD2-dependent HIF-α degradation and oxygen-induced retinal microvascular obliteration, and imply that PHD2 may be a promising therapeutic target to prevent oxygen-induced retinopathy.
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