[Effect of human bone marrow mesenchymal stem cell transplantation on hematopoietic recovery of irradiated mice].

This study was aimed to investigate the effect of human bone marrow mesenchymal stem cells (hBMMSC) on the hematopoietic recovery of sublethally irradiated mice. Female BALb/c mice irradiated with (60)Co γ-ray at a single dose of 6 Gy received graded doses of hBMMSC (1×10(5), 1×10(6) and 5×10(6)) by intravenous infusion. The counts of leukocytes, platelets, erythrocytes and hemoglobin level in peripheral blood, the amount of bone marrow hematopoietic progenitors, and the serum levels of human TPO, SCF and G-CSF as well were evaluated at different time points after transplantation. The results showed that hBMMSC infusion had little protective effect on the survival of irradiated mice. Compared with the control mice, the peripheral blood cell counts of hBMMSC-treated mice were not obviously elevated during 3 weeks after infusion, however, blood cell counts were significantly greater at 4 weeks after cell treatment (P < 0.05). The amount of colony-forming unit of mononuclear cells and granulocyte/monocytes in bone marrow of mice that received middle and high doses of hBMMSC were dramatically greater than that in control mice (P < 0.05). Two days after hBMMSC administration, human G-CSF and SCF could be detected in the sera from hBMMSC-treated mice, and the G-CSF concentration of mice that received high-dose hBMMSC was significantly higher than that in other groups (P < 0.01). Nevertheless, human TPO was undetectable in the sera of all mice tested and serum human G-CSF and SCF could not be detected on days 9 and 16 in all groups. It is concluded that hBMMSC may promote the hematopoietic recovery of irradiated mice, probably by transient secretion of hematopoiesis-associated factors by the implanted cells.