GFAP and NeuN double-labeling in C57BL6/J and iNOS-/- mice, one and two weeks after axotomy. Observe the strong upregulation of GFAP labeling in C57BL6/J (WT, F) and iNOS-/- (N) one week after lesion, as compared to the unlesioned side (B and J). The iNOS-/- unlesioned side (J) shows milder basal astroglial labeling as compared to control mice. After lesioning the astroglial reaction presented a diffuse distribution surrounding the axotomized pool of motoneurons in WT mice (G), and was more concentrated around the motoneurons in iNOS-deficient mice (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) GFAP and NeuN double-labeling on the unlesioned side of C57BL6/J and iNOS-/- mice. (H and P) GFAP labeling in C57BL6/J and iNOS-/- mice, two weeks after axotomy, lesioned side. (D and L) GFAP labeling in C57BL6/J and iNOS-/- mice, two weeks after axotomy, unlesioned side. (Q) Graph representing quantification of the integrated density of pixels for GFAP in the neuropil of the unlesioned and lesioned sides, one (1 w) and two weeks (2 w) after axotomy. * = p < 0.05, ** = p < 0.01 and *** = p < 0.001 (Student t test). Scale bar = 50 μm.