MORPHOFUNCTIONAL CHARACTERISTICS OF RAT SARCOMA M-1 AFTER PHOTODYNAMIC THERAPY WITH THE BACTERIOCHLOROPHYLL A DERIVATIVE

The study of the functional morphology of rat sarcoma M-1 after photodynamic therapy using bacteriopurpurinimide disulfide derivative (disulfide-BPI) as a photosensitizer is described. The research methods included immunohistochemistry for PCNA and CD31, evaluation of mitotic activity and apoptosis of tumor cells, as well as computer analysis of microscopic images. Photoinduced antitumor effect was shown to be due to the destruction of sarcoma M-1 vascular bed, the rapid inhibition of proliferative activity and devitalization of tumor cells by apoptosis and necrosis. It is reasonable to suppose that in the early stages after photodynamic therapy destruction of the microvasculature and photocytostatic shock of tumor cells with subsequent development of necrosis are caused by direct influence of the light flux on sensitized cellular elements in parenchyma and stroma of tumors. The efficiency of photodynamic therapy with the novel photosensitizer is determined by the sequence of destructive and inflammatory changes in tumor parenchyma and surrounding tissues, as well as repopulation potential of tumor cells survived after treatment.