Abstract
Last year, we had reported the accumulation of Hematoporphyrin derivative (HpD) in atheroma as shown by the fluorescence of HpD in vitro using the endoscopical excimer pulse dye laser fluorescence spectrophotomater. This time we tried the in vivo study. Atherosclerotic lesions were induced in rabbits by an atherosclerotic diet and balloon damage. The rabbits were received an injection of 5 mg/ kg of HpD in an ear vein, and detection procedures were started 24 hours later. As a light source, an argon dye laser was employed. The laser beam was transmitted via a quartz fiver inserted through the light guide of an ultra-thin angioscopic catheter. The spectral data of HpD were fed into polychrometer and detected by an optical multichannel analyzer.
A cut down was performed over just below the arch from which the fiberscope was introduced and pased into the left femoral artery for 1cm by 1cm. At all points, the spectra of fluorescence were detected and recorded after flushing with saline. In the normal area, only unshifted emission peaks at 610 nm and 670 nm were seen, and the ratio of the fluorescence intensity in the normal area to that in atheroma was 1:20. In the area of fatty plaque and atheroma, emission peaks at 630 nm and 690 nm were obserbed. However the emission peak at 660 nm appeared in atheroma. This study should provide impetus for further investigations regarding the affinity of HpD for atherosclerotic lesions and its possible clinical application.
