The work is devoted to the study of structural and functional changes in the lungs of rats with bleomycin-induced pulmonary fibrosis and the activity of recovery processes in them under the influence of transplanted allogeneic bone marrow stem cells. In particular, on the 45th day of pulmonary fibrosis modelling, haematological parameters change: an increase in the number of red blood cells by 8,7 % (p≤0,01); a simultaneous decrease in the average red blood cell volume by 6 % (p≤0,01). Under these conditions, blood viscosity increases, its movement in the capillaries becomes more difficult, and the volume of blood supply to tissues decreases. A decrease in haematocrit by 5 % (p ≤ 0,05) compared to the baseline indicates the presence of chronic inflammation, which is known to produce free radicals and oxidative stress. Throughout the entire period of pulmonary fibrosis modelling, an increase in haemoglobin content was noted, which on day 45 was 17 % (p≤0,01) higher than the baseline. The number of platelets on day 45 of the pulmonary fibrosis model increased by 3 % compared to the baseline. During this period, the mean erythrocyte volume decreased by 12,4 % (p≤0,001). A high level of leukocyte count was also recorded: on day 14 of the experimental pulmonary fibrosis modeling, it was 21 % (p≤0,01) higher than in the baseline condition, on day 45 of the modeling, this indicator decreased to physiological parameters, but was 21 %
(p ≤ 0,01) higher than in the baseline condition (up to 12,7 ± 0,1 G/L). An increase in lactate dehydrogenase activity in the blood of experimental animals by 33,6 % (p ≤ 0,001) on day 45 of the model indicates a violation of the integrity of lung tissue cell death. On day 45 of pulmonary fibrosis modelling, the number of macrophages in the bronchoalveolar lavage remained reduced by 51 % (p≤0,001) compared to the
baseline. It was dominated by lymphocytes (p≤0,001). X-ray images on day 45 of fibrosis modelling in the treated animals revealed areas of increased intensity in the lung tissue associated with an exudative inflammatory reaction in the alveoli and bronchioles. A small amount of free fluid was detected in the pleural cavity. The ratio between live body weight and lung weight in experimental animals gradually decreased during the period of modelling experimental fibrosis. The use of bone marrow stem cells in animals with bleomycin-induced pulmonary fibrosis contributed to a significant acceleration of the recovery processes in pathologically altered lung tissue. Оn the 45th day after the application of stem cells into the pleural cavity and intravenously, a decrease in the number of red blood cells was recorded. Moreover, the number of red blood cells decreased by 23 % and 26 % (p≤0,001), respectively, compared with the control. In animals undergoing drug treatment, a decrease in the number of red blood cells by 18 % (p≤0,001). The average volume of red blood cells on day 45 after the application of stem cells into the pleural cavity and intravenous administration increased by 31 % and 30 % (p≤0,001), respectively, compared to the control. In the case of medical treatment, this indicator decreased by only 2 % compared to the control. On day 45 after the application of stem cells into the pleural cavity, the haematocrit was 21 % higher (p≤0,001) compared to the control group. When stem cells were administered intravenously, the above-mentioned index was 14 % (p≤0,01) higher than in the control group of animals. In the case of drug treatment, the haematocrit value was 8,7 % lower in the animals than in the control group. The haemoglobin content on day 45 after the application of stem cells into the pleural cavity was higher by 13,8 % (p≤0,01) compared to the control group. When stem cells were administered intravenously, the haemoglobin content was also 10,8 % higher than in the control group. In the case of drug treatment, the haemoglobin content was the highest (14 % higher than in the control group). An increase in the number of platelets was noted, in particular: when stem cells were injected into the pleural cavity and intravenously, their total number was 33 % (p≤0,001) and 32 % (p≤0,001) higher, respectively, compared to that of the control group. Under drug treatment, the platelet count was only 2,4 % higher than in the control group. The mean platelet volume also increased in animals of all experimental groups: after injection of stem cells into the pleural cavity – by 13 % (p≤0,01), after intravenous injection of stem cells – by 10 % (p≤0,001), after drug treatment – by 8 % (p≤0,01). Based on the results obtained, the possibility of using allogeneic bone marrow stem cells to restore damaged lung structures in animals with pulmonary fibrosis
after appropriate preclinical and clinical trials was confirmed.
