Granulocyte colony-stimulating factor (G-CSF) mobilizes bone marrow-derived cells into injured spinal cord and promotes functional recovery after compression-induced spinal cord injury in mice

The aim of the present study was to elucidate the effects of granulocyte colony-stimulating factor (G-CSF)-mediated mobilization of bone marrow-derived stem cells on the injured spinal cord. Bone marrow cells of green fluorescent protein (GFP) transgenic mice were transplanted into lethally irradiated C57BL/6 mice. Four weeks after bone marrow transplantation, spinal cord injury was produced by a static load (20 g, 5 min) at T8 level. G-CSF (200 microg/kg/day) was injected subcutaneously for 5 days. Immunohistochemistry for GFP and cell lineage markers was performed to evaluate G-CSF-mediated mobilization of bone marrow-derived cells into injured spinal cord. Hind limb locomotor recovery was assessed for 6 weeks. Immunohistochemistry revealed that G-CSF increased the number of GFP-positive cells in injured spinal cord, indicating that bone marrow-derived cells were mobilized and migrated into injured spinal cord. The numbers of double positive cells for GFP and glial markers were larger in the G-CSF treated mice than in the control mice. Luxol Fast Blue staining revealed that G-CSF promoted white matter sparing. G-CSF treated mice showed significant recovery of hind limb function compared to that of the control mice. In conclusion, G-CSF showed efficacy for spinal cord injury treatment through mobilization of bone marrow-derived cells.