Red laser photodynamic therapy of melanoma b16 in an experimental model in vivo

Introduction: In recent decades, the incidence of melanoma among European population has been steadily increasing. In addition, the age of patients with this pathology is declining - today more than half of patients with melanoma are under 65 years. Melanoma is an aggressive metastatic tumor that is difficult to treat. The tumor is resistant to chemotherapy and radiotherapy. However, the mechanism of photodynamic action differs from the mechanism of cell damage by antitumor drugs or ionizing radiation. Therefore, there is a high probability that with the help of photodynamic therapy it will be possible to overcome the resistance of melanoma cells to damage. Materials and methods: The study was performed on melanoma tumors of B16 mice. The due methylene blue (MB) was used as a photosensitizer through the known affinity of this colorant to the melanin pigment of melanoma cells. The experiments used the radiation of two semiconductor lasers (Fotonika Plus, Cherkasy. Ukraine) with a wavelength of 660 nm, which corresponds to the maximum absorption of methylene blue. Results:The possibility of increasing the anti-melanoma photodynamic activity of MB with the help of a modifier - the natural polysaccharide chitosan was studied. B16 melanoma has been shown to be sensitive to PDT with MB and its sensitivity can be increased by using MB with the natural polysaccharide chitosan, which has immunoadjuvant properties. Conclusion: As a result of the presented research, a variant of PDT of B16 melanoma of mice was developed using MB sensitizer and chitosan immunoadjuvant, which includes intratumoral injection of MB together with chitosan, irradiation of tumors with a red laser with a wavelength of 660 nm, as well as the use of chitosan as an immunomodulatory factor.