Fig. 4

a Typical images of cross sections stained with Masson’s trichrome (collagen: blue, muscle fibers: red) in all experimental groups at day 28. Scale bars 50 μm. b The percentage of collagen area in all experimental groups at 3, 7, 15, and 28 days after muscle injury. Values are means ± SEM. n = 3–5/group at each time point. See Fig. 1 for the abbreviations. ^#,§Significant main effect of treatment and time revealed by two-way ANOVA, respectively (p < 0.05). ^¶Significant interaction between treatment and time revealed by two-way ANOVA (p < 0.05). *^,†,‡Significantly different from Con, BPVC, and Ice groups in the same time point, respectively (p < 0.05). ^aSignificantly different from day 3 in each group (p < 0.05)