Fig. 6: MuSC-specific Lama2 knockout delays regeneration.

a Experimental approach: three days after the last tamoxifen injection, TA muscles from control and MuSC-Lama2KO mice were collected as uninjured (UI) controls, or they were injured by cardiotoxin injection and collected at 4 and 10 DPI. b Quantification of TA masses at 4 and 10 DPI. Injured TA masses are normalized to the contralateral uninjured TA’s mass (green dotted line). At 4 DPI, n = 9 control mice; n = 12 MuSC-Lama2KO mice. At 10 DPI, n = 8 control mice; n = 9 MuSC-Lama2KO mice. c Representative immunostaining of control and MuSC-Lama2KO TA cross-sections in uninjured conditions, and at 4 and 10 DPI (EGFP in green, Pax7 in magenta, Ki67 in orange, DAPI in blue). d Quantification of the proportion of Ki67+/Pax7+/EGFP+ cells pre- and post-injury (average of 3 sections per mouse). e and f Quantification of the number of Pax7+/EGFP+ (e) and Myogenin+/EGFP+ (f) cells per 100 fibers pre- and post-injury (average of 3 sections per mouse). g Quantification of the relative number of fibers per cross-section post-injury, shown as a percentage of the number of fibers in the contralateral uninjured TA (green dotted line). h Representative immunostaining of control and MuSC-Lama2KO TA cross-sections at 4 DPI (EGFP in green, laminin-α2 in magenta, DAPI in blue). Orange arrows: fully-fused muscle fibers that are homogenously filled with EGFP and surrounded by a basement membrane; yellow arrow: presence of laminin-α2 on the apical side of EGFP+ cells in ghost fibers. i Quantification of the proportion of fully-fused EGFP+ fibers at 4 DPI (average of 3 sections per mouse). In d–f, n = 4 mice in uninjured conditions. In d–g, and i, n = 5 mice at 4 and 10 DPI. Data are means ± SEM. Statistical significance was determined by unpaired Student’s two-sided t-test (i) or two-way ANOVAs with Bonferroni’s multiple comparisons test (b, d–g). *P < 0.05; ***P < 0.001; ****P < 0.0001. Source data and P-values are provided as a Source Data file. a Created in BioRender. Ruegg, M. (2025) https://BioRender.com/d18khcw.