Neuronal GSK3β deletion increases axonal growth. (A) Representative images of GSK3β immunohistochemistry in DRG neurons from cre+GSK3βwt/wt (cre+wt/wt) mice and cre+GSK3βlox/lox (cre+lox/lox). Scale bar: 50 μm. (B) Quantification of the intensity ratio of the P-CRMP-2/βIII-tubulin and P-MAP1B/βIII-tubulin immunostainings depicted in C; CRMP-2/βIII-tubulin (n = 63 to 65 growth cones) and P-MAP1B/βIII-tubulin (n = 70 to 77 growth cones). (C) Neurite outgrowth in naïve DRG neurons from cre+GSK3βwt/wt and cre+GSK3βlox/lox mice quantified as the percentage of neurons with the longest axon within each range: <75 μm, 75 to 200 μm, or ≥200 μm; (n = 48 to 66). (D) Representative images of sagittal spinal cord sections following dorsal hemisection, from cre+GSK3βwt/wt and cre+GSK3βlox/lox mice. YFP+ axons are shown in green and dorsal column fibers traced with CT-B are labeled in red; higher magnifications of cre+GSK3βwt/wt and cre+GSK3βlox/lox showing the YFP+/CT-B+ axons (arrowheads) within the glial scar are shown on the right. r: rostral; c: caudal; d: dorsal; v: ventral. Scale bar: 25 μm. (E) Number of CT-B+YFP+ axons able to enter the glial scar in cre+GSK3βwt/wt and cre + GSK3βlox/lox mice; (n = 4 to 5). (F) Percentage of lesion area occupied by YFP+ axons (% YFP within lesion area) in cre+GSK3βwt/wt and cre+GSK3βlox/lox mice; (n = 4 to 5). (G) Locomotor recovery in cre+GSK3βwt/wt and cre+GSK3βlox/lox mice assessed by Basso Mouse Scale following complete spinal cord transection. All error bars are SEM. *P <0.05. ***P <0.001. Two-tailed Student’s t test. CRMP, collapsin response mediator protein; GSK3β, glycogen synthase kinase 3β; MAP1B, microtubule-associated protein 1B; SEM, standard error of the mean; YFP, yellow fluorescent protein.