Morphofunctional Characteristics of Lung Macrophages in Rats with Acute Respiratory Distress Syndrome

A comprehensive morphofunctional study of the lungs and alveolar macrophages was carried out in Sprague-Dawley rats with acute respiratory distress syndrome (n=10) induced by intratracheal administration of E. coli LPS 0111:B4 in a dose of 15 mg/kg. On the first day after LPS administration, bronchopneumonia was observed in the lungs, the number of macrophages of the bone marrow origin and the number of M1 macrophages with the proinflammatory phenotype in the bronchoalveolar lavage increased, the expression of proinflammatory cytokines increased and the expression of anti-inflammatory cytokines decreased, which was accompanied by an increase in LPS and C-reactive protein in the blood serum. The revealed changes correspond to the development of acute respiratory distress syndrome in humans, and the decrease in the number of macrophages in the lungs and their predominant polarization to the M1-proinflammatory phenotype substantiate the use of cell therapy with reprogrammed M2 macrophages.