Fig. 6.
Functional assays of AP-EXOR&L&S in the spinal cord crush model. Adult mice were subjected to spinal cord crush and received intravenous injections of AP-EXO or AP-EXOR&L&S beginning at day 1 after contusion at the dose of 1 mg/kg/week for 5 weeks. The BMS scores of the mice were then determined weekly for 6 weeks. Four weeks after injury, BDA was intra-cortically injected to trace CST axons (a) Schematic timeline of the dose regimen for the study of AP-EXO and AP-EXOR&L&S in spinal cord crush mice. i. v. Is short for intravenous injection. (b–c) BMS score assessment of spinal cord crush mice treated with AP-EXO or AP-EXOR&L&S. b, BMS scores at the end of the treatment. c, BMS scores in consecutive week. (SCI: n = 9, AP-EXO: n = 9, AP-EXOR&L&S: n = 9. *p < 0.05, #p < 0.05, One way ANOVA on ranks post Turkey test). (d) Sagittal spinal cord sections of the three treated groups showing BDA-labeled CST axons on composite tiled scans. Sections were also stained for cell nuclei (DAPI, left), mature neurons (NeuN, middle) and astrocytes (GFAP, right). Solid lines demarcate astrocyte proximal (PB) and distal (DB) borders around the lesion core (LC). Scale bar: 500 μm. (e) Representative magnified images showing BDA-labeled CST regrowth across the proximal borders, sections were stained for astrocytes. Scale bar: 100 μm. (f) Axon density of CST fibers across the proximal and distal border. (SCI: n = 5, AP-EXO: n = 5, AP-EXOR&L&S: n = 5. *p < 0.05, #p < 0.05, **p < 0.001, −500 μm, −250 μm, 0 μm, 750 μm, 1000 μm, 1250 μm, 1500 μm, one-way ANOVA post Student-Newman-Keuls test. 250 μm, 500 μm, one-way ANOVA on ranks post Tukey test. *dominated as comparison between the SCI group and the AP-EXOR&L&S group, # denominated as comparison between the SCI group and the AP-EXO group). (g) BDA-labeled terminals (red) beyond the lesion overlapped with the presynaptic (white) and postsynaptic (green) markers synaptophysin (Syn1) and postsynaptic density protein 95 (PSD95), respectively. Scale bar: 10 μm. (h–i) BDA-labeled terminals (red) juxtaposed with ChAT-positive motor neurons (white) and vGLUT1-positive boutons (green) or GAD67-positive boutons (green) below the injury. Scale bar: 10 μm.