Oxygen-induced retinopathy in newborn rats: effects of prolonged normobaric and hyperbaric oxygen supplementation.

An experimental study was conducted to verify the effects of prolonged normobaric and hyperbaric oxygen supplementation on retinal vessels in newborn animals. Nine litters of newborn Wistar rats were used in the following way. Two litters were used as controls. Two other litters received normobaric oxygen supplementation (FiO2 80%) for five days after birth. These rats were then removed and kept for five more days in room air. Retinopathy with marked peripheral retinal neovascularization was seen in these litters. Three other litters were exposed to the same treatment for ten days after birth, removed from oxygen, and kept for 15 more days in room air. Severe retinopathy with extraretinal proliferation and, in some cases, retinal detachment developed in these animals. Two other litters received hyperbaric (1.80 atm) oxygen supplementation (FiO2 80%) for ten days after birth and were then kept for 15 days in normobaric room air. These animals showed no evidence of peripheral retinopathy. It is possible that moderate hyperbarism exerts, in the newborn rat, a protective action against the toxic effects of oxygen supplementation on immature retinal vessels.