Natural course of experimental retinal vein occlusion in rabbit; arterial occlusion following venous photothrombosis.
BACKGROUND
Retinal vein occlusion (RVO) is the second leading cause of vascular eye disease. Currently there is no definite treatment for this condition. Animal models could be potentially helpful in developing new treatments; however, it is essential to understand the differences these models may have with human RVO. The aim of our study was to examine the course of experimentally created retinal vein occlusion (RVO) in rabbits.


METHODS
Twenty-nine pigmented rabbits were included in the study. RVO was created in all using an argon green laser following intravenous injection of Rose Bengal. A laser was applied to all major veins at the optic disc margin to mimic central retinal vein occlusion. Animals were followed-up for a maximum of 2 months.


RESULTS
Immediately following laser application, blood flow ceased or the flow was extremely slow in the retinal veins in all cases. At day 2 post laser, 86% showed significant retinal hemorrhages. On FA, no retinal blood flow was observed in the eye (neither arteries nor veins) in the majority of rabbits. Between weeks 1 and 3, laser sites reopened and partial or complete revascularization of both retinal arteries and veins occurred; however, the vascular pattern was abnormal.


CONCLUSIONS
RVO in rabbits has a different course than in human and it can be classified into three stages. At stage 1 (the first few days after laser photothrombosis), there is a retrograde propagation of the blood clot in the retinal veins that extends to the retinal arteries and choriocapillaries. As a result, there is no retinal blood flow at this stage in most cases. At stage 2 (between weeks 1 and 3), partial or complete revascularization occurs but the vessels have an abnormal pattern. At stage 3 (after week 3) no significant change takes place.
Ameri
Hossein
H
Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA. hameri@doheny.org
Ratanapakorn
Tanapat
T
Rao
Narsing A
NA
Chader
Gerald J
GJ
Humayun
Mark S
MS
D000818:Animals; D004396:Coloring Agents / Q000008:administration & dosage; D004195:Disease Models, Animal; D005451:Fluorescein Angiography; D005500:Follow-Up Studies; D007208:Indocyanine Green; D007275:Injections, Intravenous; D007429:Intraocular Pressure; D017075:Laser Coagulation; D054020:Lasers, Gas; D010781:Photography; D011817:Rabbits; D012039:Regional Blood Flow; D015356:Retinal Artery Occlusion / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012166:Retinal Hemorrhage / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012169:Retinal Vein / Q000503:physiopathology* / Q000601:surgery; D012170:Retinal Vein Occlusion / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012395:Rose Bengal / Q000008:administration & dosage; D013997:Time Factors; D041623:Tomography, Optical Coherence
D004396:Coloring Agents; D012395:Rose Bengal; D007208:Indocyanine Green