Abstract
Purpose: :
To evaluate the use of intravitreal t–PA within and without liposomes, in an experimental rabbit model of retinal vessel photothrombosis.
Methods: :
5 rabbits, 10 eyes were been thrombosed using a photodynamic technique, and the natural course of thrombosis were monitored for 45 days. Two similar groups were prepared, and intravitreal injections of 60 µg tPA and 15 µg of tPA encapsulated in liposomes were performed immediately after thrombosis, and the course of thrombosis was compared to controls. T–PA penetration to the vascular lumen was studied with immunohistochemistry assay.
Results: :
Retinal vessels remain occluded for more than 45 days after photothrombosis. Although differences were noticed at injection groups as micro–haemorrhages and PVD, no evidence of circulation restore was present. Immunohistochemistry shown no definite evidence of t–PA, nor t–PA entrapped in liposomes, penetration into the vascular lumen.
Conclusions: :
t–PA and t–PA encapsulated in liposomes, seems not to be able to change the natural course of retinal vein thrombosis, in this experimental model.
Keywords: vascular occlusion/vascular occlusive disease • pharmacology • photodynamic therapy