[Experimental study on earlier thrombogenic process in thrombin induced retinal venous obstruction in rabbit eye]

The purpose of this study was to morphologically investigate the thrombogenic process in the early stage of retinal venous obstruction development. Venous obstruction was induced by transadventitial instillation of thrombin (5 units) given to the rabbit retinal vessels via a sclerovitreous route. The changes were studied by ophthalmoscopy, fluorescence microscopy combined with an intravenously injected gelatin fluorescein preparation technique as well as light and electron microscopy. No ophthalmoscopic change was seen within 1 hr after thrombin instillation. Three hour after thrombin instillation, focal narrowing of retinal arterioles was found with intraluminal platelet aggregation and rouleaux formation of erythrocytes. On electron microscopy, a large number of monocytes was observed in the lumina and subendothelial space of a pericytic venule having a partial endothelial defect as well as monocyte adhesion to its luminal surface. At more than 6 hrs, subendothelial thrombi were observed in the venules without any endothelial lesion while no change was observed in the arterioles, capillaries and pericytic venules. These findings suggested the possibility of participation of the arteriolar lesion in the occurrence of retinal venous obstruction and the role of endothelial lesions caused by blood stasis in subendothelial thrombogenesis.