Fig. 5

IHC staining of CD31 positive cells in different groups after transplantation of hydrogel (A). CD31⁺ cells are indicated using black arrows. In the control group, CD31⁺ cells with flattened morphology are juxtaposed with normal myocytes in the muscular tissue. In the Col group, numerous CD31⁺ cells can be detected within the injection site without a regular pattern, indicating the promotion of angiogenesis due to immunological response. Data indicated more aligned CD31⁺ cells in the Col + Cells group. The intensity and number of CD31⁺ cells were reduced in Col/Keratin and Col/Keratin + Cells groups. CD31⁺ cells can be detected at the periphery of newly generated myofiber in the Col/Keratin + Cells group. Westernblotting analysis of MyoD and myosin (B; n = 3). Data revealed the induction of MyoD in Col + Cells and Col/kertain + Cells groups, indicating the maturation of muscle progenitor cells. Despite the increase of myosin in the Col/Kertain + Cells group, the differences were statistically non-significant. One-way ANOVA analysis with Tukey test. *p < 0.05; ***p < 0.001; and ****p < 0.0001