Fig. 6: Combination of PLG bridge implantation and hNSC transplantation enhances axonal regeneration and oligodendrocytic myelination.

a–g Immunostaining for total axonal regeneration (NF-H, green) counterstained with a nuclear marker (Hoechst, blue) of SCI control and PLG bridge implanted spinal cord sections. White dashed lines outline the lesion (ipsilateral side) and tissue interface in both control and PLG groups. a NF-H in a horizontal mouse spinal cord section (C5 left hemisection injury) in which the PLG bridge shows robust axonal regeneration from both the rostral and caudal parenchyma at 6WPI; b, c insets show higher power. d NF-H in a transverse spinal cord section in a SCI control mouse 16 WPT; e inset shows higher power. f NF-H in a transverse spinal cord section in a PLG bridge implanted mouse 16 WPT; g inset shows higher power. h, i Triple immunostaining for NF-H labeled axons (NF-H; green), oligodendrocyte-derived myelin (MBP; red) and Schwann cell myelin (P0; blue) in PLG bridge implanted spinal cord sections. Boxes indicate regions shown at higher magnification with 3D surface masks representing examples of unmyelinated axons (j quantified in n), oligodendrocyte myelinated axons (k quantified in n and p), and Schwann cell myelinated axons (l, m; quantified in n, q). n Total NF-H⁺ axon volume and axon proportional myelination status within the SCI control lesion and PLG bridge. The graph represents Mean ± SEM; n = 4–6 mice/group. o Total NF-H volume. p NF-H volume associated with oligodendrocyte myelin. q NF-H volume associated with Schwann cell myelin. Graphs represent Mean ± SEM; n = 5–6 mice/group. Statistical comparisons were conducted using unpaired Student’s t-tests two-tailed (***p ≤ 0.001). r STEM121⁺ processes (red) wrapped around NF-H axons (blue) in the middle of a channel at 26 WPT. s Co-localization of STEM121 (red) human-specific hNSC marker with MBP⁺ myelin (green) and NF-H⁺ axons (blue) in the PLG bridge at 26 WPT. t mT-mNSC exhibit close alignment with regenerated axons in the PLG bridge identified by NF-H⁺ (blue). u, v mT-mNSC exhibit close alignment with regenerated CST axons in the PLG bridge identified by CRYM-GFP⁺ (green). Scale bars: a, d, f 200 μm; b, c 50 μm; e, g–i, r 10 μm; j–m 2 μm; s 1 μm; t–v 5 μm.