Subcutaneous tumors of mice treated with rhodamine-123 and laser irradiation.

Abstract

Background: Treatment involving photosensitizers and laser irradiation (LIR) in cancer therapy is known as photodynamic therapy (PDT). The purpose of our study was to assess the therapeutic effect of PDT using rhodamine-123 (Rh123) and LIR on subcutaneous tumors (ST) in mice.

Methods: Sarcoma-180 cells (1 x 10(7)) were implanted subcutaneously into the breast area of strain Cr1:CD-1-ICR (BR) female mice. Mice bearing ST were treated with Rh123 or LIR alone, or a combination of both, once a day for 3 successive days.

Results: The best therapeutic effect was observed in the group treated with 7.5 mg Rh123 per kilogram of body weight, combined with 75 J/cm2 laser irradiation energy. The group's mortality rate, tumor control rate, mean survival time, and increase in lifespan within 120 days after treatment were 16.7%, 83.3%, 109.4 days, and 135.8%, respectively. The most inhibitory effect on tumor cells was found in the group treated with 15 mg/kg Rh123 and 90 J/cm2 laser irradiation. The biosyntheses of DNA, RNA, and protein in tumor cells of this group was obviously inhibited.

Conclusion: PDT with the photosensitizer Rh123 and laser irradiation was therapeutically effective in treating subcutaneous tumors of mice. The tumor cells and the syntheses of DNA, RNA, and protein of the tumor cells in these PDT treated mice were obviously inhibited.