Fig. 3

Histological evaluation of the fiber thickness by Masson’s trichrome and Sirius red staining. A Masson’s trichrome staining on samples obtained by days 7 and 21. B Sirius red staining on samples obtained by days 7 and 21 and examination under polarized light mode. Comparison of the fiber thickness was conducted among three groups as well as between the time points of days 7 and 21. Statistical significance was analyzed by independent samples t test or one-way ANOVA followed by a Tukey post hoc analysis between two or multiple groups, respectively. *P < 0.05, **P < 0.01, ## P < 0.01. Scale bars, 1 mm. PL polarized light mode of microscope