Abstract
Purpose:
To establish a reliable, reproducible rat retinal edema model by applying 532nm Nd:YAG laser with Erythrosin B intravenous infusion, and to observe the morphological changes of retina and vascular leakage.
Methods:
Retinal edema was induced in adult SD rats by photochemical reaction. According to Brant D. Watson’s method, the experimental eyes were immediately subjected to a Nd:YAG laser beam (532nm, 1.95±0.05mw, Diameter=5mm) for 8 minutes after intravenous Erythrosin B (20mg/kg) infusion. At several times points (0, 1, 2, 3, 5, 7 and 14 days) after edema induction, the morphological changes of retina and vascular leakage were observed using fundus photography, Fluorescein Angiography (FA) and Optical Coherence Tomography (OCT).
Results:
Retinal Edema was observed by OCT immediately after induction. The thickness and vascular damage were progressed over time. In the second day following induction, the retinal thickness reached to the peak, including subretinal fluid, vascular narrowing and vasodilatation, but no photothrombosis. The retinal thickness before induction was 218.67±2.04μm at 0.5mm from optic nerve disc (OND), and increased to 282.67±6.48μm in the first day after induction, then reached to 302.08±7.00μm in the second day after induction. The edema last for 5 days, then decreased to 233.75±8.85μm in the fifth day after induction. In the fourteenth day, the thickness was decreased to 197.50±6.48μm, which is less than the control level (P<0.05).
Conclusions:
Retinal edema created by photochemical induction is a reproducible and reliable animal model for mimicking human retinal edema without vascular occlusion.
Keywords: 505 edema •
552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
578 laser