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Tadashi Matsumoto, Yuta Saito, Takashi Itokawa, Masahiko Tomita, Kota Yokoyama, Chiaki Yui, Tomoaki Shiba, Haruo Takahashi, Yuichi Hori; The effect of intravitreal injection of anti-VEGF antibody on ocular circulation in a rat model of retinopathy of prematurity. Invest. Ophthalmol. Vis. Sci. 2018;59(9):5465.
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We investigated the effect of intravitreal injection of anti-vascular endothelial growth factor (VEGF) antibody on ocular circulation in rats with oxygen-induced ischemic retinopathy (OIR), a model for retinopathy of prematurity.
50/10 OIR rats were used for this study. The rats received intravitreal injections to the right eye on postnatal day (p) 14. We compared the effects of intravitreal injection of 1 µg of either the anti-VEGF antibody (16 rats, VEGF group) or IgG (15 rats, control group). Body weight, heart rate, and ocular perfusion pressure (OPP) were measured before measurement of ocular blood flow. Ocular blood flow (mean blur rate; MBR) was measured on p18 (8 VEGF group and 8 controls), and on p25 (8 VEGF group and 7 controls) using Laser speckle flowgraphy (LSFG) -Micro. After measurement of blood flow, the rats were killed and the retinas in the right eyes were fixed, flat-mounted, and stained with ADPase. Retinal neovascularization was scored using the counting clock hours method (CH). Avascular areas (AVA) were measured as a percentage of the total retinal area (%AVA).
There were no significant differences between the two groups in body weight, heart rate, OPP, or %AVA on p18 or p25. On p18, the MBR was significantly lower in the VEGF group than in the control group (10.1 ± 2.4 vs. 14.1 ± 3.7; p = 0.02), but on p25, there was no significant difference between the two groups. On p18, the CH was not significantly different between the two groups, but on p25, it was significantly lower in the VEGF group than in the control group (3.6 ± 2.1 vs. 7.1 ± 3.2; p = 0.01).
Previous reports have shown that intravitreal injection of anti-VEGF antibody decreases intraocular VEGF levels and improves retinopathy in OIR. Additionally, we reported that ocular blood flow and retinal VEGF levels of OIR rats were greater than those of rats exposed to only room air on p18. In this study, the CH on p25 was lower in the anti-VEGF-treated group than in the controls. This is considered to be due to the angiogenesis-inhibiting effect of anti-VEGF. The MBR of the anti-VEGF-treated group on p18 was lower than that of controls, but there was no significant difference between the two groups on p25. These findings suggest that MBR and intraocular VEGF are related, and that MBR is an indicator of the severity of retinopathy in OIR.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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