Suppression of laser-induced choroidal neovascularization by oral tranilast in the rat

PURPOSE. To determine whether tranilast administered to pigmented rats inhi bits formation of choroidal neovascularization induced by diode-laser photo coagulation. METHODS. Female Brown Norway rats were used. On day 0, choroidal neovascula rization was induced by diode-laser photocoagulation, using a setting of 75 mu m spot size, 0.1 second's duration, and 100 mW intensity. Tranilast (20 0 or 600 mg/kg per day) was administered orally twice daily for 14 days. In domethacin (1 and 5 mg/kg per day) was administered orally once a day for 1 4 days. Choroidal neovascularization was evaluated on days 7 and 14 by fund us photography and fluorescein angiography. Late-phase fluorescein angiogra phy was scored according to four grades. The animals were killed on day 14, and the lesions were evaluated histologically. RESULTS. In the vehicle-treated group, 34 of 35 burns (97%) showed fluoresc ein staining and late leakage on day 14. Choroidal neovascularization was i dentified by light microscopy in all the lesions that showed fluorescein st aining and late leakage. The score of fluorescein staining was reduced in r ats given 200 mg/kg per day or 600 mg/kg per day (P < 0.01) of tranilast. t he thickness of the laser-induced lesions was reduced in a dose-dependent m anner by tranilast, a significant difference was observed with 600 mg/kg pe r day (P < 0.05). Oral indomethacin treatment did not reduce fluorescein st aining on day 14. CONCLUSIONS. Tranilast inhibits the development of choroidal neovasculariza tion in this experimental model.