Overexpression of G-CSF improves motoneuron survival following sciatic nerve axotomy in neonatal pups. (A) Quantification of the absolute number of α; motoneurons per section of the lumbar spinal cord on the contralateral (unlesioned) side. Numbers are not significantly different between the three genotypes studied. (B) On the axotomized side numbers of detectable motoneurons are dramatically decreased in the littermate animals lacking the CaMK-tta driver transgene (wt, BEG -/- CaMK-/-; and BEG -/T CaMK-/-), whereas overexpression of G-CSF in the CNS results in significantly higher numbers of surviving motoneurons (***p < 0.0001 by ANOVA and Fisher's LSD post-hoc analysis). (C) Percentage of surviving motoneurons on the ipsilateral (axotomized) relative to the corresponding contralateral (control) side. While only 50 - 60% of the motoneurons survive in the genotypes lacking the CaMK-tta driver transgene, close to 90% of the motoneurons survive in the presence of the driver (i.e. in animals overexpressing G-CSF) (***p < 0.0001 by ANOVA and Fisher's LSD post-hoc analysis). (Number of animals: wt, n = 13; BEG -/T CaMK -/-, n = 6; BEG -/T CaMK -/T, n = 7; 6 sections were studied per animal).