Abstract
Abstract: :
Purpose: Several new surgical trials for central retinal vein occlusion, such as radial optic neurotomy and direct vein cannulation, have recently been reported, but pathophysiological evaluation of those procedures has not yet been conducted. One of the reasons for that is a lack of an appropriate experimental model. Laser- or diathermy-induced vein occlusion causes mechanical damage to the vessels and surrounding tissue. Intravitreal thrombin injection induces intravascular thrombosis and retinal hemorrhage, which are mild and transient. To improve the thrombin instillation model, we employed repeated thrombin applications after polidocanol injection to obstruct veins extensively. Methods: Twelve pigmented rabbits weighing approximately 2 kg were anesthetized with intramuscular Ketamine and Xylazine injection. A total of 0.05ml polidocanol (1%) was injected around the optic nerve through the vitreous, followed by 0.05 ml of Thrombin (1000U/ml) intravitreal injection on the surface of the optic disc. Thrombin injections were repeated twice at intervals of three days. Fluorescein angiography and histological examination were performed at 7 and 14 days after the final thrombin injection. Results: Vein dilation and retinal bleeding were observed in all eyes. Fluorescein angiography showed reduced and delayed retinal circulation. Thrombin in veins and red blood cells in the neural retina were observed by histological examination. Conclusions: This model pathologically resembles retinal vein occlusion. It could therefore be useful for evaluating therapies for central retinal vein occlusion.
Keywords: vascular occlusion/vascular occlusive disease • animal model