Morphological changes in erythrocytes against the background of photodynamic therapy using Bacteriochlorin in animals with malignant neoplasms

Morphological changes in red blood cells are the primary indicators of the effects of various origins. During photodynamic therapy (PDT), the microstructures of pathological tissues and their vascular (microcirculatory) bed are damaged and disrupted, while the main visible changes appear directly at the site of irradiation, and reliable data on the transformation of red blood cells in animals have not been previously described. The photosensitizer "Bacteriochlorin" is a modern and effective compound for PDT due to its optical properties and activation at a wavelength of 750 hm. Currently, there is also insufficient data on the effect of photosensitizers from the bacteriochlorin group on the structural and functional state of the surface of red blood cells and other specific toxic changes occurring with blood cells. This study showed that photodynamic therapy using bacteriochlorin has the same effect on morphological changes in red blood cells in both dogs and cats. The identified cases of poikilocytosis after PDT were insignificant and cannot be unambiguously associated with this photosensitizer. There was also a moderate decrease in erythrocyte aggregation, which manifested itself in shortening the chains of "coin columns", probably due to the activation of tissue respiration. Along with this, an increase in the number of lymphocytes and monocytes was noted, which indirectly indicates an increase in the activity of cellular immunity. Among all animals, there was a slight decrease in erythrocyte mass (4.5%), hemoglobin (8.5%) and hematocrit (4.9%). There were no allergic reactions in the form of an increase in the number of eosinophils in 6 animals of the experimental group and the 1st control animal, and no other side effects associated with the administration of PS were detected. As a result of the conducted research, it was concluded that photodynamic therapy using the Bacteriochlorin photosensitizer is safe for red blood cells, provided that optimal dosages of the injected substance are observed, time intervals and laser irradiation power are precisely observed.