Object: Granulocyte colony-stimulating factor (G-CSF) has neuroprotective effects on the CNS. The authors have previously demonstrated that G-CSF also exerts neuroprotective effects in experimental spinal cord injury (SCI) by enhancing migration of bone marrow-derived cells into the damaged spinal cord, increasing glial differentiation of bone marrow-derived cells, enhancing antiapoptotic effects on both neurons and oligodendrocytes, and by reducing demyelination and expression of inflammatory cytokines. Because the degree of angiogenesis in the subacute phase after SCI correlates with regenerative responses, it is possible that G-CSF's neuroprotective effects after SCI are due to enhancement of angiogenesis. The aim of this study was to assess the effects of G-CSF on the vascular system after SCI.
Methods: A contusive SCI rat model was used and the animals were randomly allocated to either a G-CSF-treated group or a control group. Integrity of the blood-spinal cord barrier was evaluated by measuring the degree of edema in the cord and the volume of extravasation. For histological evaluation, cryosections were immunostained with anti-von Willebrand factor and the number of vessels was counted to assess revascularization. Real-time reverse transcriptase polymerase chain reaction was performed to assess expression of angiogenic cytokines, and recovery of motor function was assessed with function tests.
Results: In the G-CSF-treated rats, the total number of vessels with a diameter > 20 μm was significantly larger and expression of angiogenic cytokines was significantly higher than those in the control group. The G-CSF-treated group showed significantly greater recovery of hindlimb function than the control group.
Conclusions: These results suggest that G-CSF exerts neuroprotective effects via promotion of angiogenesis after SCI.