Myeloid Precursors in the Bone Marrow of Mice after a 30-Day Space Mission on a Bion-M1 Biosatellite.

The content of myeloid stem CFU in bone marrow karyocytes from the tibial bone of C57Bl/6 mice was evaluated after a 30-day Bion-M1 pace flight/ground control experiment and subsequent 7-day recovery period. After the space flight, we observed a significant decrease in the number of erythroid progenitors in the bone marrow, including common myeloid precursor - granulocyte, erythrocyte, monocyte/macrophage, megakaryocyte CFU. After 7-day readaptation, CFU level in flight animals did not recover completely. In the ground control, the count of erythroid burst-forming units was higher than in vivarium animals. Comparison of the changes observed in fight and ground experiments demonstrated effects associated space flight factors and manifesting in suppression of the bone marrow erythropoiesis.