The early administration of granulocyte colonystimulating factor increases the engraftment of transplanted bone marrow-derived cells into the olfactory epithelium damaged by methimazole

In 2005 we reported that transplanted bone marrow-derived cells were engrafted into the olfactory epithelium and then had characteristics of olfactory neuron cells. However, the engraftment rate was far from a practical level. Granulocyte colony-stimulating factor (G-CSF) is known to mobilize stem cells from the bone marrow into the circulation. To assess the efficacy of G-CSF on engrafting transplanted bone marrow-derived cells into the olfactory epithelium, we performed the time window study of G-CSF administration. After C57BL/6 mice transplanted with bone marrow cells from GFP mice received selective damage of the olfactory epithelium by methimazole, G-CSF was administrated into the recipient mice at different time windows. A statistical analysis demonstrated that the early administration of G-CFS was appropriate to increase the engraftment rate of bone marrow-derived cells into the olfactory epithelium. Cells with double-immunostaining for GFP and OMP, GAP43 or cytokeratin were found in the olfactory epithelium of recipient mice. These results suggest that bone marrow-derived cells are engrafted as stem cells of the olfactory tissue and that the early administration of G-CSF is more effective to increase the engraftment rate of bone marrow-derived cell into the olfactory epithelium damaged by methimazole.