Fig. 4.

Laminin-α1 is essential for SC proliferation. a Control and Lama1^cko Tibialis anterior (TA) muscle analyzed at 14 days post injury by Haematoxylin and Eosin staining, and immunofluorescence for laminin-α2 (green), MyoD (red), and collagen I (red). Black and white arrowheads indicate the presence of smaller regenerated myofibers in Lama1^cko mice. White arrows indicate sites of fibrosis. The graph shows the minimal Feret diameter analysis of control and Lama1^cko TA muscles at 14 dpi. Scale bar, 50 μm. n = 3 per genotype. b Number of MyoD⁺ cells in injured TA muscles at 2, 4, and 7 dpi in control and Lama1^cko mice. n = 3 per genotype. c Number of Ki67⁺ cells in injured TA muscles at 2 and 4 dpi in control and Lama1^cko mice. d Quantification of the number of satellite cells activated (blue), proliferating (yellow), self-renewing (green), and differentiating (purple) in a 72-hour ex-vivo culture of control, heterozygous, and Lama1^cko myofibers. n = 3 per genotype with 31–79 myofibers per time point. Graphs show mean + sem. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 (t-test for b, c, and d, and one-way ANOVA for a)