Fig. 3

Syndecan-3 loss increases myofiber hypertrophy and myonuclear accretion in repeatedly injured muscles and improves muscle aging. a Wild type (WT) and Sdc3 ^−/− (S3−/−) TA muscles harvested 3 weeks after three successive injuries and stained to detect laminin (red) and nuclei (blue). b Myofiber cross-sectional area of Sdc3 ^−/− (S3−/−, black bars) and wild type (WT, white bars) from uninjured TA muscles and TA muscle injured with two or three successive BaCl₂ injections (insets indicate median cross-sectional area in μm²). c, d Quantification of regenerating myofibers with centrally located nuclei after two (c) and three (d) successive injuries. e Fibrosis indicated by collagen staining is reduced in TA muscles from aged (2 years old) Sdc3 ^−/− mice compared to TA muscles from age- and sex-matched wild type mice. f Quantification of (e). g–h Myogenin + cells (g) and the percent of centrally nucleated myofibers (h) in TA muscles from 2 years old Sdc3 ^−/− mice are increased compared to TA muscles from age- and sex-matched wild type mice. Scale bars are 30 μm in a and 50 μm in e. Error bars are S.E.M. ** = p < 0.01; * = p < 0.05