Figure 5.

LAR blockade with peptides ELP and ILP significantly recovers neurite outgrowth in DRG neurons and CGNs cultured on CSPGs. A, C, DRG neurons derived from adult C57BL/6 mice and CGNs from postnatal 7–9 d C57BL/6 mice were cultured in the absence or presence of CSPGs (1.5 μg/ml) plus vehicle (Veh), RP, ELP, or ILP. Neurons were fixed and stained with an antibody against βIII-tubulin 24 h after growth. Both ELP and ILP significantly recovered neurite length of DRG neurons and CGNs on CSPGs. Scale bar, 50 μm. B, D, Immunostaining indicates LAR expression in the soma and neurites of DRG neurons and CGNs. The scale is the same as in A. E–G, Neurite length per DRG neuron was quantified 24 h after cell plating. ELP and ILP treatments increased neurite length in the presence of CSPGs compared with cells treated with Veh or RP (E), but did not significantly alter neurite length in the absence of axonal growth inhibitor (F) or in the presence of CNS myelin (G). H, Neurite length per CGN was quantified 24 h after cell plating. ELP and ILP treatments increased neurite length of CGNs in the presence of CSPGs compared with cells treated with Veh or RP. In the graphs in E–H, the numbers indicate means ± SEM from four to six coverslips (8–10 images/coverslip) in each group. *p < 0.05, **p < 0.01, Student's t test.