SHORT COMMUNICATION: The vitreous protein concentration is increased prior to neovascularization in experimental ROP

Abstract

PURPOSE. To test the hypothesis that the vitreous protein content is altered prior to the development of neovascularization in an experimental model of retinopathy of prematurity (ROP). METHODS. Newborn rats underwent either a variable oxygen exposure or room air exposure following birth. On day 13 or 14, two days prior to neovascularization, the steady state vitreous and plasma total protein levels in room-air controls or variable-oxygen-exposed newborn rats were determined; similar measurements were also made for control adult rats. RESULTS. There was a significant difference (P < 0.05, 2-tailed t-test) in the vitreous protein concentration between the age-matched control and experimental newborn rats. The protein level in the ROP rat plasma was not significantly (P > 0.05) different from that in the age-matched control animals. The vitreous-to-plasma-protein ratios of both the control and ROP new- born animals were significantly greater (P < 0.05) than that in the adults. CONCLUSIONS. The results of this study demonstrate, for the first time, increased vitreous protein levels prior to the development of neovascularization in the newborn rat model of ROP. In addition, developmental changes in vitreous protein levels were identified. The role of developmental and pathologic alterations in the blood-ocular barriers in this study is discussed.