VISUALIZATION AND FLOW OF PLATELETS AND LEUKOCYTES IN-VIVO IN RAT RETINAL AND CHOROIDAL VESSELS

Purpose: To directly visualize the flow of leukocytes in choroidal ves sels and the flow of platelets in retinal vessels in a rat without inc ision by fluorescein leukocyte angiography (FLA) using a scanning lase r ophthalmoscope (SLO). Methods: Blood was withdrawn from a tail vein of a Sprague-Dawley rat with a tuberculin syringe traced with sodium h eparin and mixed with sodium fluorescein. The fluorescent plasma layer was diluted with saline solution, centrifuged and then the overlying plasma discarded. The remaining cell suspension was diluted with salin e to create the original hematocrit, then infused into the vein of the same rat while performing fluorescein angiography with an SLO. The an giographic image was recorded on a videotape using time-lapsed photogr aphy. Results: Fluorescent platelets were detected and the flow within the retinal vessels traced over time, Fluorescent leukocytes in the c horoidal vessels were also detected and the flow of a leukocyte was tr aced and its relative velocities were plotted against the time sequenc e. The relative size and fluorescence intensities of the platelets and leukocytes in the angiographic image corresponded well with the smear of the blood preparation. Conclusions: FLA using an SLO can be used t o detect the flow of platelets in the retinal vessels and the flow of leukocytes in the choroidal vessels in the experimental rat eye model.