Fig. 7: mECM@IL4 + PM@IGF1 composites promote muscle regeneration in the volumetric muscle loss (VML) model of rats at 2 and 8 weeks.

A Schematic diagram of muscle regeneration enhanced by the injectable composites. B Macroscopic images of VML treated with different materials on day 0, and muscle regeneration at 2 and 8 weeks post-treatment. C–E H&E, Masson staining and desmin (green) immunofluorescence images showing muscle regeneration. Nuclei in (E): blue; black dotted box: high magnification images; P: porous microspheres; white dashed line: the boundary between microspheres and tissues. F The muscle mass ratio of the injured side/normal side. The floating bars represent the range of minimum to maximum values, and the line inside the box represents the mean value (n = 3 biologically independent samples). *P < 0.05, one-way ANOVA, multiple comparisons. G Statistical analysis of collagen deposition in (D). Data are presented as mean ± SD (n = 3 biologically independent samples, three random fields per sample). ****P < 0.0001, *P < 0.05, one-way ANOVA, multiple comparisons. H Statistical analysis of desmin fluorescence intensity in (E). Data are presented as mean ± SD (n = 3 biologically independent samples, 2 random fields per sample). ***P < 0.001, **P < 0.01, *P < 0.05, one-way ANOVA, multiple comparisons. I–N, O–T Frequency distribution statistics of the cross-sectional area (CSA) of neonatal myofibers at 2 and 8 weeks. Data are presented as mean ± SD (n = 3 biologically independent samples, 25 random myofiber areas per sample).