FIG. 5.

Enhanced neurite outgrowth in response to a preconditioning sciatic nerve crush is reduced in neurons plated on glycated fibronectin. Representative photomicrographs of neurons from L4 and L5 DRG ipsilateral to a crush injury to the sciatic nerve (7 days before culture), which were dissociated and plated on fibronectin (A, D, and G), fibronectin glycated with methylglyoxal (B, E, and H), or fibronectin treated with methylglyoxal in the presence of aminoguanidine (C, F, and I) for 18 h with (D–I) or without (A–C) neurotrophin treatment (D–F, 50 ng/ml GDNF; G–I, 10 ng/ml NGF). The preconditioned neurons extend neurites in the absence of neurotrophic support (A–C); this was enhanced by neurotrophin treatment (D–I). Two parameters of neurite extension were quantified: total neurite outgrowth (J, cross points) and length of longest neurite (K). Neurons plated on glycated fibronectin showed a significant reduction in length of longest neurite and total neurite density compared with control, which was prevented by inclusion of the glycation scavenger aminoguanidine (C, F, and I–K) and also by NGF (H, J, and K). All data are expressed as means ± SD, n = 4 independent experiments (ANOVA with Bonferroni post hoc test, *P < 0.05). Scale bar = 100 μm. AG, aminoguanidine; FN, fibronectin; MG, methylglyoxal.