Advantages of laserphyrin compared with photofrin in photodynamic therapy for bile duct carcinoma

Abstract

BACKGROUND: The aim of this study was to compare the effects of laserphyrin-PDT (L-PDT) on biliary cancer with those of the conventional photosensitizer, photofrin-PDT (P-PDT). METHODS: An animal tumor model was established by inoculation of NOZ cells in 4-week-old male BALB/c mice. The laser light wavelength was set at 630 nm for P-PDT and 660 nm for L-PDT, at a frequency of 10 Hz. Each group received a total energy flux of 60 J/cm(2). The proportion of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling)-positive cells, expression of VEGF (vascular endothelial growth factor) and the PCNA (proliferating cell nuclear antigen)-labeling index (LI) were assessed after PDT. RESULTS: L-PDT had significantly more potent apoptotic effects at 48 and 72 h after light exposure compared with P-PDT (P < 0.001). The mean PCNA-LI was significantly lower in the L-PDT group than the P-PDT group and the index was significantly lower at several time points after PDT (6, 12, 24, 48 and 72 h after laser light exposure) in the L-PDT than P-PDT (P < 0.001 vs. control). The cell proliferative activity was significantly decreased at 12 and 24 h after P-PDT compared with the control (P < 0.001). VEGF expression was significantly higher at 3 h after L-PDT compared with the control (P < 0.05), whereas it was significantly higher at many time points after P-PDT (3, 6, 48 and 72 h; P < 0.05 vs. control). CONCLUSIONS: L-PDT is a better approach for biliary cancer than the conventional P-PDT, based on its potent apoptotic and cytostatic effects.