Photodynamic treatment for atherosclerotic plaques of the rabbit abdominal aorta by the laparoscopical approach using a pheophorbide derivative

Abstract

A new photosensitizer, PH-1126, was administered intravenously into the ear veins of cholesterol-fed atherosclerotic rabbits at a dose of 1 mg/kg of body weight. At 24 hr after PH-1126 administration, the atherosclerotic abdominal aorta was irradiated with a krypton ion laser with a wavelength of 647 nm by 100 J/cm2 by the laparoscopical approach. Twenty-four hours later, the abdominal aorta irradiated by the laser beam was excised for histological analysis. In the atherosclerotic plaques with photodynamic treatment, damaged foam cells were observed by scanning electron microscopy and transmission electron microscopy. Some of these cells were exposed to the aortic lumen. No significant changes were shown in the abdominal aorta either with plaques not injected with PH-1126 or without plaques after photodynamic treatment. These findings suggest that atherosclerotic plaques of the abdominal aorta could be selectively degraded by laparoscopical photodynamic treatment.