Antiapoptotic Effect of Granulocyte-Colony Stimulating Factor After Peripheral Nerve Trauma

Abstract

Granulocyte-colony stimulating factor (G-CSF) has been observed to have direct protective effects on neurons after stroke in experimental models and in humans. In the present study, the antiapoptotic effects of G-CSF on spinal α-motoneurons after inducement of peripheral sciatic nerve lesions were evaluated in a rat model. Of 48 rats, 24 were treated with G-CSF and 24 were treated with glucose 5% solution (control group). The spinal cord of 6 rats in each group were removed at days 1, 4, 7, and 14. The α-motoneurons of spinal cord section L4-L6 were counted and investigated for the expression of choline acetyltransferase (ChAT), G-CSF receptor (G-CSFR), and Bcl-2 and Bax proteins. Additionally, α-motoneuron fluorescence double staining was performed for ChAT/Bcl-2, ChAT/Bax, and ChAT/G-CSFR. Without G-CSF treatment, the number of ChAT-positive α-motoneurons on the lesion side was significantly decreased (P < 0.001). The number of α-motoneurons with Bcl-2 and G-CSFR positivity on the lesion side was significantly decreased (P < 0.05). In contrast, the number of α-motoneurons with Bax positivity was significantly greater (P < 0.05). After G-CSF treatment, the differences in the number of α-motoneurons on the 2 sides were not statistically significant. Fluorescence double staining of α-motoneurons was positive for ChAT/Bcl-2, ChAT/Bax, and ChAT/G-CSFR. The results indicated that G-CSF has neuroprotective properties in spinal α-motoneurons and contributes to antiapoptotic effects after peripheral nerve lesions. The relevance of G-CSF, its precise mode of action, and the effect of these findings in clinical situations remains to be elucidated and require examination in further studies.