Reactions of the blood system and stem cells in bleomycin-induced model of lung fibrosis

On the model of toxic diffuse pulmonary fibrosis induced by intratracheal administration of bleomycin, we studied reactions of the blood system, content of stem cells, committed hemopoietic and stromal progenitor cells in the bone marrow, spleen and peripheral blood of C57Bl/6 mice. It was shown that the development of diffuse pulmonary fibrosis was accompanied by hyperplasia of bone marrow hemopoiesis and leukocytosis in the peripheral blood. Activation of the erythroid and granulocytic hemopoietic stems was related to stimulation of hemopoietic stem cells (polypotent cells, granulocyte/erythroid/macrophage/megakaryocyte precursor cells) and committed erythroid and myeloid progenitor cells in the bone marrow. At the same time, the number of stromal precursors increased. Bleomycin increased the count of hemopoietic stem cells the peripheral blood and spleen and reduced the content of mesenchymal stem cells in the spleen and bone marrow.