The enhancement of CCL2 and CCL5 by human bone marrow-derived mesenchymal stem/stromal cells might contribute to inflammatory suppression and axonal extension after spinal cord injury
Fig 9
Microglia/macrophage (MG/MΦ) polarization and axonal regeneration were enhanced by CCL5.
To determine whether increases in CCL5 following hMSC transplantation contribute to MG/MΦ polarization and axonal regeneration, recombinant mouse CCL5 (rmCCL5, n = 6 mouse) or vehicle (n = 6 mouse) was injected into the spinal cord on postoperative day (pod) 7. We examined levels of gene expression for MG/MΦ polarization (A-C) and axonal regeneration (D and E) 24 hours after injection. There were no obvious differences in the levels of the pan-macrophage marker Aif1 (A). Expression of the M2-type AAM marker Chil3 (B) significantly increased following the injection of rmCCL5 (p<0.01). Although Arg1 expression (C) also tended to increase, these increases were nonsignificant. Expression of the axonal regeneration marker Gap43 (E) significantly increased following the injection of rmCCL5 (p<0.05), while Dpysl2 (D) expression tended to increase (p = 0.097). All data are expressed the relative level (fold) to compare with vehicle treated animals (n = 6 mouse) after normalization against Gapdh as a housekeeping gene. Data are expressed as the mean ± SEM. **: P < 0.01, *: P < 0.05 (Dunnett’s post hoc test).