Fig. 1
From: Fate decision of satellite cell differentiation and self-renewal by miR-31-IL34 axis
Deletion of miR-31 in mice impairs skeletal muscle regeneration. a Real-time RT-PCR of miR-31 expression levels in TA muscle from day 0 to day 7 after BaCl2 injury. b In situ hybridization of miR-31 in regenerating skeletal muscle 3 days post injury. Scale bar: 20 μm. c Absolute body weight of adult WT and miR-31-KO mice. d Relative uninjured TA muscle wet weight of adult WT and miR-31-KO mice. e Representative photomicrographs of H&E-stained sections showing a delayed regeneration of injured TA muscle in miR-31-KO mice compared with that in WT littermates at day 5 (N = 4) after BaCl2 injection. Scale bar: 200 μm. f Regenerating myofiber size (percentage) distributions of WT and miR-31-KO TA muscle 5 days after BaCl2-mediated injury were measured by using ImageJ software. Only myofibers that contained centrally located nuclei were counted. **P < 0.01; ***P < 0.001. g Quantification of the ratio of regenerating myofibers containing two or more centralized nuclei per field at day 5 post injury. N = 4 in each group. ***P < 0.001. h Representative overlaid photomicrographs of TA muscle sections of WT and miR-31-KO mice 5 days post injury after immunostaining for eMyHC (red) and laminin (green). Nuclei were labeled by DAPI. Scale bar: 30 μm. i Average CSA of eMyHC-positive fibers in TA muscle 5 days post injury. ***P < 0.001. j Sixty days after the first injury, a second injection of BaCl2 solution was delivered to the muscle of WT and miR-31-KO mice, and the muscle was analyzed at day 5 after the second injury. An H&E-stained TA muscle section from a miR-31-KO mouse presenting severely delayed muscle repair after being subjected to a second injury. Scale bar: 30 μm. k Quantitative analysis of the average CSA of regenerating myofibers at day 5 after the second injury. N = 3 in each group. ***P < 0.001. l Experimental procedure presenting SC preparation and transplantation into the regenerating TA muscle of WT mice. m Histology analysis of the 5-day recovered TA muscles of WT mice transplanted with SCs by performing H&E staining. Scale bar: 50μm. n Quantification of the average myofiber CSA of regenerating TA muscles transplanted with SCs of adult WT mice 5 days after injury. N = 3 in each group. ***P < 0.001
