Fig 1: Blocking S100B early after acute muscle injury delays regeneration. (a) BaCl2-injured TA muscles were injected with IgG or a polyclonal anti-S100B antibody (Abcam No. ab41548) at d1 p.i. Treated muscles were excised at d3, d7 or d14 p.i. (b) Histology of muscles and counts of interstitial cells and centrally nucleated myofibers. (c) Counts of PAX7+, MyoD+, myogenin+, Ki67+, and RAGE+ cells (also see Fig. S1d,e). (d) Western blots of the indicated proteins in homogenates of IgG- and anti-S100B-treated muscles. Immunoblots of GAPDH and a-actinin are included as loading controls. (e) Myofiber size distribution at d14 p.i. in uninjured muscles and IgG- and anti-S100B-treated injured muscles. (f) Migration of primary mouse myoblasts in Boyden chambers in the absence or presence of S100B. Full-length blots are presented in Supplementary Fig. S7 “Fig. 1”. Results are means ± SEM (n = 6). **p < 0.01, ***p < 0.001 vs. control. The scale bar represents 50 µm in (b) and 200 µm in (f).