Long-term effectiveness of photodynamic therapy by using a hydrophilic photosensitizer ATX-S10(Na) against experimental choroidal neovascularization in rats.
OBJECTIVE
We previously demonstrated that a hydrophilic photosensitizer ATX-S10 had a potent photodynamic effect. This study was designed to reveal the long-term effectiveness of photodynamic therapy (PDT) with this agent in occluding choroidal neovascularization (CNV) and its selectivity in the neovascular tissue.


METHODS
Experimental CNV was induced by intense photocoagulation in rat eyes. Immediately or 2 hours after intravenous injection of 8 mg/kg body weight of ATX-S10(Na), a cis isomer of ATX-S10, eyes were irradiated by a diode laser at the radiance of 3.25-65.3 J/cm(2) Vascular occlusion was identified by fundus photography, fluorescein angiography, and histology at 1, 3, 7, 14, and 28 days after PDT. As controls, non-neovascular eyes were subjected to PDT and similarly analyzed.


RESULTS
By using the following treatment parameters, PDT with ATX-S10(Na) successfully occluded CNV without causing occlusion of retinal capillaries for 28 days; 7.4 and 19.6 J/cm(2) immediately after dye injection and 36.7 and 65.3 J/cm(2) 2 hours after injection. Although these conditions also caused occlusion of normal choriocapillaries and mild injuries of retinal vessels, retinal pigment epithelium, and photoreceptors at 1 day, retinal vessels and pigment epithelial cells recovered from damages by 28 days. No injuries were found in the inner retina.


CONCLUSIONS
In optimal treatment conditions, PDT with ATX-S10(Na) can induce long-term, selective occlusion of CNV without causing irreversible damages in the inner retina.
Kanai
M
M
Department of Ophthalmology, Osaka City University Medical School, Osaka 545-8585, Japan.
Obana
A
A
Gohto
Y
Y
Nagata
S
S
Miki
T
T
Kaneda
K
K
Nakajima
S
S
D000818:Animals; D002829:Choroid / Q000098:blood supply* / Q000187:drug effects*; D009389:Neovascularization, Pathologic / Q000188:drug therapy*; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011166:Porphyrins / Q000627:therapeutic use*; D051381:Rats; D012160:Retina / Q000187:drug effects; D013997:Time Factors
C115550:ATX-S10; D017319:Photosensitizing Agents; D011166:Porphyrins