Olfactory ensheathing cells promote neurite outgrowth of developing, but not mature NT2 neurons. Human developing neurons (2wk RA) were co-cultured with Schwann cells (A) and ensheathing cells from the olfactory mucosa (B) and the olfactory bulb (C) for 24 h. (D) OB-OECs showed a permissive effect for elongation of the longest neurite compared with PDL, Schwann cells and OM-OECs but not with laminin. (E) Neurite outgrowth on OB-OECs resulted in a significant increase of total length compared with all other substrates and cell types. (F) Number of neurites is increased for neurons seeded to Schwann cells, OM-OECs and OB-OECs but not for neurons seeded to a laminin or PDL coating. (G- I) Mature neurons grown on canine Schwann cells (G), mucosal (H) and bulbar ensheathing (I) cells. (J) Elongation of the major neurite was not significantly increased when seeded to canine glia (K) Total length of neurites was neither affected by glial cells when compared with control (L) Number of neurites appeared slightly, but not significantly reduced for neurons grown on OM-OECs. Cells were fixed and stained for β-III-Tubulin (magenta) and DAPI (cyan) after 24 h of co-culturing. Histograms present the means ± SEM of 4–5 experiments (2wk RA) and 2–3 experiments (hNT2). Statistical analysis was performed using Kruskal-Wallis-test (***p < 0.001, **p < 0.01, *p < 0.05). Scale bar is 50 μm.