A new photosensitizer, NPe6, was administered intravenously into the ear vein of cholesterolfed atherosclerotic rabbits at a dose of 5mg/kg of body weight. At 6 hours after NPe6 administration, the atherosclerotic lesions of the abdominal aortas were irradiated by a diode laser at 664nm of wavelength with 200J/cm2. The abdominal aortas irradiated by laser beam were digested with NaOH, excised for histological analysis using, the scanning electron microscopy.
There are a number of methods of removing all nonelastin tissues from the aortas from which we have chosen the hot alkaline method originally proposed by Lowry et al and recently modified by Ushiki. This method is designed for preserving the natural organization of elastin components in the digested aorta. The architecture of the elastic fiber networks in the atherosclerotic plaque irradiated by a diode laser were destroied and the clumps of debris were occasionally observed. These findings suggested that the architecture of the elastic fiber network in the atherosclerotic plaque were destroied by photodynamic therapy.