Angiotensin-II as a Trigger Factor in the Development of Retinopathy of Prematurity

Abstract

The multifactorial nature of the retinopathy of prematurity (ROP) pathogenesis, makes the thorough study of the mechanism of pathological retinal neovascularization actual. However recently the attention of scientists has been attracted by the participation of renin-angiotensin system (RAS) in the development of retinal vasoproliferative diseases. Purpose: to study the role of AT-II in the pathogenesis of experimental ROP (EROP) in the original model of the disease. Material and methods. To reproduce EROP Wistar rats (n = 15) were exposed to the oxygen concentration varying from 60 to 15% every 12 hours for 14 days from the first day after birth followed by room air for 7 days. Throughout the experiment, the room maintained a constant temperature (+26 °C) and light regime (12 hours a day, 12 hours a night) modes. Control rats (n = 12) were born and kept under normal oxygen content (21 %). Batches of EROP (n = 5) and control (n = 4) rats were sacrificed on 7, 14 and 21 days. All rats underwent binocular enucleation, after which every eyeball was opened on the limb, the cornea and lens were removed with the remains of a persistent vascular bag and a hyaloid artery. Retinas were isolated, homogenized and stored at -20 °C. Angiotensin-II (AT-II) in homogenates was measured using the IFA kit. Results. On the 7th day of the experiment, the level of AT-II in the retina of the experimental group rats was 0.19 ± 0.02 pg/mg protein that was significantly higher than in controls (0.12 ± 0.01 pg/mg protein). On the 14th and 21st days concentrations of AT-II in EROP and control groups had no significant difference. Conclusion. On the 7th day of the experiment, i.e. at the period corresponding to the existence of avascular retinal zones in both groups concentration of AT-II in the retinas of rats with EROP was significantly higher than in controls. This fact indicate the role of this proangiogenic factor in the induction of pathological neovascularization in ROP. Possible prognostic function of this parameter during the period before ROP manifestation has undoubted practical significance.

Studying the Pathogenesis of Retinopathy of Prematurity - From Theory to Practice

“…With regard to AT-II in the experiment, we obtained data that at the time which corresponded to the presence of avascular areas of the retina, its retinal level in rat pups with OIR was statistically sig- nificantly higher than in rat pups of the control group, which may indicate a pro-angiogenic role of this participant in the induction of pathological neovascularization in OIR, as well as a possible prognostic role before the onset of the disease [13].…”

“…We carried out a comprehensive clinical and experimental study, including an assessment of the local and systemic level of 49 cytokines of various biological effects, 4 monoamines and one of the most important components of the renin-angiotensin systemangiotensin-II (AT-II) at different stages of the development of the pathological process [5,[8][9][10][11][12][13][14].…”