hADSCs promote axonal regeneration.

<p>A–D) Photomontages showing the expression pattern of 5HT-positive serotonergic fibers in horizontal sections spanning the pre- and post-lesion regions in DMEM (A) and hADSC (B) treated animals one week after compression. The inset shows an example of a hogback termination in the post-lesion area. Note that the hADSC-treated cord exhibits a larger number of serotoninergic fibers crossing the injury site. C) Graph representing the total length of 5-HT fibers in each experimental group (n = 3 in each group). D–E) 5HT expression was greatly reduced in the chronic phase (8 wks) in DMEM-treated rats (D), while it was slightly reduced in hADSC (E) treated group. F) Quantification of the total length of 5-HT positive axons, eight weeks after SCI (n = 3 in each group). G–R) Progression of axonal regeneration was followed by Tuj1 (G–L) or anti-GAP-43 (M–R) immunoreactivity. Panels on the left show Tuj1 (G, J) or GAP-43 (M, P) positive fibers one week after compression at the epicenter of the lesion. Panels H, K, N, Q and rows on the right show respective rostral (left), epicenter (center), and caudal (right) regions of the same section eight weeks after SCI. Far column on the right (yellow frame) shows boxed areas in higher magnification. The dashed line indicates the border of the lesion cavity. Graphics show the quantification of the total lengths of Tuj1 (I, L) or GAP-43 (O, R) positive fibers one week (I, O) and eight weeks (L, R) after SCI in the peri-cavity region (n = 3 in each group). Tuj1 and GAP-43 positive axons in DMEM (blue) and hADSC (red) treated groups were quantified in an area of approximately 900 µm in extension along the longitudinal axis. Both white and grey matter was analyzed. The y-axes in panels F, I, L, O and R were omitted for aesthetic purpose and they represent fiber length per area (µm/µm²×10³). The values in C, F, I, L, O, R represent means ± standard errors. *P<0.05, **P<0.01, ***P<0.001. Bars: A, B = 500 µm, D–Q = 100 µm, high magnification = 50 µm.