Fig. 4

Neurite outgrowth from dorsal root ganglia (DRG) explants in the different culture conditions. a–e Confocal microscopy images of E16 rat DRG explants placed on a coverslip (a), on poly-caprolactone (PCL) filaments (c), on PCL filaments + msenshymal stem cells (MSC) (d), and on PCL filaments + MSC + Schwann cells (SC) (e) and cultured for 72 h. Neurites are identified by immunolabeling with NF-200 (green) and cell nuclei with To-Pro (blue). b Nomarski DIC image showing the organization of PCL filaments in these experiments. Dashed circles illustrate the area where DRGs were placed (b–e). f–h High-magnification confocal optical sections showing enhanced green fluorescent protein (EGFP) + MSCs (green) on PCL filaments (f) 72 h after incubation with DRG (thick arrows indicate MSC-EGFP and thin arrows indicate migrated non-MSC on PCL filaments). In (g), neurites were immunolabeled for NF-200 (red) and the merged image reveals neurites growing aligned in close association with MSC (h, arrows). i,j Histograms of quantitative analysis of maximum neurite extension (i) and neurite density on PCL filaments at 500 μm from DRG (j) after 72 h of incubation. Scale bars: a = 400 μm; b–e = 200 μm; f–h = 50 μm. *p < 0.01, **p < 0.001, ***p < 0.0001, ANOVA