Abstract
Purpose: :
Macular edema is one of the serious side effects following retinal scatter laser photocoagulation. It has been suggested that accumulated leukocytes in retina might be involved in the augmented vascular permeability, resulting in retinal edema after laser photocoagulation. In this study we quantitatively evaluated the inhibitory effect of triamcinolone acetonide (TA) on leukocyte–endothelial cell interactions following scatter laser photocoagulation in vivo.
Methods: :
Argon laser photocoagulation was performed in one half of the retina in male Brown–Norway rats (100 µm, 0.05 sec, 50 mW, 400 spots). TA–treated rats were received posterior sub–Tenon administration of TA (2 mg), and vehicle–treated rats were given the same amount of saline (50 µl). Non–operated rats were used as controls. Leukocyte dynamics in the retinal microcirculation and retinal vessel diameters were evaluated 1 day after laser photocoagulation using acridine orange digital fluorography. Retinal thickness was evaluated with optical coherence tomography.
Results: :
In TA–treated rats, the number of rolling leukocytes and accumulated leukocytes in retina were significantly decreased by 66% (P<0.01) and 24% (P<0.05) respectively, compared with those in vehicle–treated rats. TA significantly reduced the number of leukocytes in vitreous (P<0.01) and retinal vessel diameters (artery; P<0.05, vein; P<0.01). Retinal thickness in vehicle–treated rats was significantly thicker than those in control rats 1 day after laser photocoagulation (p<0.01). Retinal thickness in TA–treated rats was significantly suppressed compared with those in vehicle–treated rats (P<0.05).
Conclusions: :
Sub–Tenon administration of TA significantly suppressed leukocyte dynamics in rat retinal microcirculation and inflammatory reaction following laser photocoagulation. Our results suggest that the suppression of leukocyte–endothelial cell interactions in retinal microcirculation may be responsible for the therapeutic effect of sub–Tenon TA on the post–laser retinal edema.
Keywords: laser • drug toxicity/drug effects • imaging/image analysis: non-clinical