Fig. 3

ST2-positive FAPs and IL-33-positive FAPs are induced upon immobilization. A Flow cytometric analysis of the FAPs population (upper) and ST2-positive FAPs (lower) using a single-cell suspension prepared from the muscles of young mice collected on days 0 and 14 of immobilization. Boxed areas indicate FAPs (upper) and ST2-positive FAPs (lower). B Number of ST2-positive FAPs per muscle weight in the TA muscles from young and aged mice collected on days 0, 3, and 14 of immobilization (n = 3). C Sections of the TA muscle of young mice stained for tdTomato (PDGFRα), IL-33, and laminin and with DAPI. Specimens were collected on days 0, 3 and 14 of immobilization. D Sections of the TA muscle of aged mice stained for PDGFRα, IL-33, and laminin and with DAPI. Specimens were collected on days 0, and 3 and 14 of immobilization. E, F Ratio of FAPs positive for IL-33 on days 0, 3 and 14 of immobilization in young (E) and aged (F) mice. Three random sections from each specimen (three mice) were evaluated. *P < 0.05; **P < 0.01. Bar, 50 μm