Abstract
Purpose: :
The present study examined the effects of bevacizumab on the level of the vascular endothelial growth factor (VEGF) and the neovascularization in a rat model of oxygen-induced retinopathy (OIR).
Methods: :
OIR was induced in 5-day-old rat pups by raising them in 75±5% hyperoxic conditions for 7 days and in normoxic conditions for the next 5 days. Dextran fluorescence retinal angiography was used to quantitatively assess OIR. Animals were divided in four groups: I. bevacizumab treated group that received intracardiac bevacizumab (25ug/10g) injection. II. control group that received intracardiac saline injection group III. sham group that received no treatment after hyperoxic condition. IV. normal group that raised in normoxic conditionVitreous concentrations of VEGF were compared among groups and the presence and severity of neovascularization, retinal vascular area, and retinal vascular density were scored in a masked manner. The retinopathy scoring system for animal models , modified from the International Criteria for Retinopathy of Prematurity system for humans, was used to quantify the severity of retinopathy.
Results: :
Vitreous concentrations of VEGF were elevated in eyes in bevacizumab non-treated group (group II and III) compared with bevacizumab treated group (group I). The median VEGF level was 43.22 ± 21.47 pg/ml in group I, 73.74 ± 5.06 pg/ml in the group II, 86.87 ± 14.85 pg/ml in group III and 54.87 ± 4.78 pg/ml in group IV. The differences in both vitreous VEGF concentrations between bevacizumab and control or sham groups were statistically significant (P=0.001 and P=0.001, respectively). The presence and severity of neovascularization, retinal vascular area, and retinal vascular density were significantly decreased in the bevacizumab-treated OIR group compared to that in the saline-administered control and non-treated sham group. The differences in retinopathy scoring system between bevacizumab treated and non-treated groups were statistically significant (P < 0.05).
Conclusions: :
These findings confirm the increase in vitreous VEGF levels in eyes with active OIR model. Anti-VEGF treatment may be of benefit in the eyes that develop OIR.
Keywords: neovascularization