[Effects of ectomesenchymal stem cells on hematopoiesis after total body irradiation]

To investigate the effects of ectomesenchymal stem cells on hematopoiesis after total body irradiation in rats.

The primary ectomesenchymal stem cells were isolated from E11.5 SD fetal mandibular processes by 2.5 g/L trypsin and cultured with DMEM/F12. The morphology and growth rate were observed by inverted microscope. Eighty SD male rats randomly divided into ectomesenchymal stem cells group (n = 20), fibroblast group (n = 20), saline group (n = 20) and control group (n = 20), the first three groups were irradiated with 60Co gamma rays at 6. 0 Gy. The number of their bone marrow nucleated cells was counted after 4 weeks; the forming ability of colony-forming unit-granulocyte macrophage (CFU-GM) and histopathology of bone marrow were also observed.

The cultured cells displayed monolayer growth and fibroblast-like with 2-4 processes. The ectomesenchymal stem cells could increase the number of bone marrow nucleated cells and peripheral blood white cell count, and improve the forming ability of CFU-GM. After 4 weeks of transplantation, the number of the peripheral blood white cells in group A was more than that in groups B and C (P < 0.05), the contents of Hb in groups A and D was significantly higher than those in groups B and C (P < 0.05). After 4 weeks, the bone marrow nucleated cells in group A were significant more than those in groups B and C (P < 0.01); CFU-GM in groups A and D was higher than that in groups B and C (P < 0.01).

Ectomesenchymal stem cells have characteristics of stem cells. It may improve hematopoiesis recovery of irradiated rats.