Fig. 9.
Hydrogel delivery of M-CSF at the site of SCI boosted microglial proliferation and enhanced functional recovery. a Quantification of the number of microglia (CD11b+ P2ry12+) in the thoracic spinal cord following intra-cisterna magna injection of recombinant murine M-CSF at various doses (n = 3 mice per group). b Schematic of the experimental design showing the timeline of spinal cord contusion (SCI), hydrogel injection, behavioral testing using the Basso Mouse Scale (BMS), and sacrifice. Below the schematic is a picture showing how much a hydrogel loaded with Evans blue spreads following subdural injection at the site of SCI. c Quantification of the number of microglia (TdT+) at the lesion epicenter at 7 days post-injury (dpi) in Cx3cr1creER::R26-TdT mice treated with either M-CSF-based (orange bar) or PBS-based (blue) hydrogels (n = 5 mice per group). d Quantitative analysis of the total lesion area at the lesion epicenter and both rostral (R) and caudal (C) at 7 dpi in mice treated with M-CSF (orange) or PBS (blue) in hydrogels (n = 9–15 mice per group). e and f Assessment of locomotor recovery using the BMS (e) and BMS subscore (f) showed that hydrogel delivery of M-CSF increased functional recovery after SCI (n = 9–10 mice per group). Data are expressed as mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, M-CSF-loaded hydrogel compared with PBS-loaded hydrogel. Statistical analysis was performed using a one-way (a, c), two-way (d), or two-way repeated-measures (e and f) ANOVA followed by a Bonferroni’s post hoc test