Abstract
The authors evaluated potential of photodynamic therapy with a new photosensitizer, mono-L-aspartyl chlorin e6 (NPe6) that tissue uptake and clearance are rapid. Firstly, NPe6 solution was exposed to diode laser at 664nm that fits to maximum absorption of NPe6. Immediately after laser exposure, these solutions were subjected to electron spin resonance (ESR) to detect generation of activated oxygen species. With ESR, signals of O2, OH, and 1O2 were detected on NPe6 solution. Contrary to this, signals of O2 and OH dissipated when dissolved with superoxide dismutase. Fundi of pigmented rabbits were then irradiated to diode laser after administration of NPe6. Histopathologically, there showed necrosis of endothelial cells and vascular occlusion in choroid, especially in choriocapillaris. Retinal pigment epithelial cells were also injured. In contrast, sensory retina was approximately preserved even with a large amount of dye. A new combination of NPe6 and diode laser at 664nm enables us to occlude choroidal vessels efficiently by generating various activated oxygens. This fact proposed potential of photodynamic therapy with NPe6 in treating retinochoroidal involvement.
