Photodynamic treatment of subcutaneous tumors in mice with photofrin II and argon ion laser

Objective. To investigate the combined effects of photofrin (Pf) II and laser irradiation on mice bearing subcutaneous tumors. Method. Ehrlich ascites tumor cells (1 x 10⁷) were implanted subcutaneously into the breast area of ICR mice. The tumors, when grew up to 0.55 ± 0.15 cm³, was administered of laser irradiation (514.5 nm, 112.5 mW/cm² for 11.12 min with a total energy 75J/cm²) after intraperitoneal injection of Pf II (5, 7.5, 10 and 15 mg/kg body weight) once a day for three successive days. Results. The mortality rate (MR₁₂₀) in the tumor control was 93.7% and the mean survival time (MST₁₂₀) was 46.6 days. The best therapeutic effect (50% mortality rate, 53.8% tumor control rate and mean survival time 86 days) was observed in the group treated with 7.5 mg of Pf II per kg of body weight and total irradiation energy of 75J/cm² (112.5 mW/cm² for 11.12 min) with 514.5 nm argon ion laser light. Conclusions. The effect on the survival rate of tumor cells and synthetic rates of DNA, RNA and protein were obviously inhibited, as the dose of Pf II and laser irradiation increased.