INFLUENCE OF BONE MARROW MESENCHYMAL STROMAL CELLS ON THE FUNCTIONING OF HEMATOPOIETIC CELLS UNDER SUBLETHAL...

investigation of the influence of mesenchymal stromal cells on the functioning of hematopoietic cellsof Balb/C mice after the exposure to ionizing radiation at a sublethal dose in cell culture in vitroand in vivo.

To study the influence of stromal microenvironment, a cocultivation model of hematopoietic cells of irradiated animals and mesenchymal cells forming feeder layers was used in the in vitro culture. Using the trypan bluedye, the number of hematopoietic cells with cytoplasmic membrane damage was assessed and the level of cell deathwas determined. Cell cultivation in the diffusion chambers culture in vivoallowed assessing the proliferative potential of bone marrow hematopoietic stem cells of irradiated animals.

Investigation of the interaction between bone marrow stromal and hematopoietic cells of Balb/C miceallowed determining the modifying influence of the stroma on the level of progenitor cells' interphase and reproductive death due to ionizing radiation action at a sublethal dose. In particular, after 2 days the percentage of deadcells in suspension with direct contact with the stroma in vitro was reduced compared to hematopoietic cells wheresuch contact was absent: (40.5 ± 2.6) % vs (60.1 ± 2.8) %. The increase in cell aggregates number was also observedin the cultures of irradiated progenitors, which had previously interacted with mesenchymal stromal cells in vitro(25.2 ± 1.9 CFU), compared to the cells, which did not directly interact with the stroma (15.3 ± 2.8 CFU).

Cocultivation with stromal cells have significantly reduced the level of radiationinduced death ofbone marrow hematopoietic cells and increased their colonyforming activity, however, this required the direct contact with stroma in the in vitroculture.