Fig. 1.

Multimodal effects of hMSCs in vitro. Compared with saline control, LPS or IFN exposure significantly augmented IDO expression (red) in both (A) nonscaffolded hMSCs and (B) PLGA-scaffolded hMSCs, as shown by human nuclei (hN) immunostaining (green; P < 0.05: *, control vs. LPS; ^#, control vs. IFN-γ; n = 5; one-way ANOVA with Tukey’s post hoc test). PLGA scaffolds showed yellow autofluorescence under dual channels. (C–E) DRG in organotypic coculture grew neurites (GAP43+, green) that track toward nearby hMSCs (CD90+, red; arrows), compared with (F) a more radial neurite pattern in DRG cultured with scaffold only (G). There were significantly more angular neurite paths in DRG and scaffolded hMSC cocultures (59.25 ± 2.9°) relative to the DRG and scaffold-alone group (48.15 ± 4.1°; P = 0.026, Student’s t test). Images showed different lengths of neurite outgrowth at the (H) distal and (I) proximal sites of axotomized DRG cocultured with PLGA-scaffolded hMSCs or scaffold alone, respectively. (J, Upper) The scaffolded hMSC and DRG cocultures had significant increases in mean total lengths when 3–20 neurites per DRG were averaged (*P = 0.032, n = 6, Mann–Whitney) and also (J, Lower) significantly increased the maximum absolute length of DRG neurite outgrow when 3–15 neurites per DRG were assessed (*P = 0.026, n = 6, Mann–Whitney). (K) Relative CNTF mRNA expression in scaffolded hMSCs was significantly elevated, as was (L) secretion of human BDNF (P < 0.05, one-way ANOVA) in the scaffolded hMSC + DRG coculture system.