Iba-1 and NeuN double-labeling in C57BL6/J and iNOS-/- mice, one and two weeks after axotomy. Observe the strong upregulation of Iba-1 labeling in C57BL6/J (WT, F) and iNOS-/- (N) one week after lesion, as compared to the unlesioned side (B and J). Two weeks after axotomy, the microglial reaction decreased (H and P). The microglia presented in close apposition to axotomized motoneurons (G and O). (A and I) NeuN labeling on the contralateral side of C57BL6/J and iNOS-/- mice, respectively. (E and M) NeuN labeling on the ipsilateral side of C57BL6/J and iNOS-/- mice, respectively. (C and K) Iba-1 and NeuN double-labeling in the unlesioned side of C57BL6/J and iNOS-/- mice. (D and L) Iba-1 labeling on the unlesioned side of C57BL6/J and iNOS-/- mice, two weeks after axotomy. (Q) Graph representing quantification of the integrated density of pixels (×103) for Iba-1 immunohistochemistry in the neuropil of the unlesioned and lesioned sides, one (1 w) and two (2 w) weeks after axotomy. * = p < 0.05 (Mann-Whitney U test). Scale bar = 50 μm. (R) Schematic representation of the sciatic nerve pool in the ventral horn of spinal cord. One motoneuron is shown in detail with apposed pre-synaptic terminals. The dashed circles represent areas where measurements of the integrated density of pixels were performed.