Fig. 2: Short-term Atf3 deletion accelerates acute injury-induced muscle regeneration.

a Schematic of the experimental design. b H&E staining of TA muscles collected at 3, 5 and 7 days post the 1st round injury (dpi). Scale bar: 50 μm. Cross-sectional areas (CSAs) of newly formed fibers were quantified from the TA muscles at 7 dpi. p = 0.000066, 0.018, 0.00069, 0.0087, 0.00082, 0.00047 and 0.046. c IF staining of eMyHC (red) and Laminin (green) was performed on the above TA muscles. Scale bar: 50 μm. p = 0.00000011. d, e H&E and eMyHC staining of the TA muscles post the 2nd round injury. Scale bar: 50 μm. p = 0.012, 0.019, 0.033, 0.0057, 0.0022, 0.0022 and 0.0093 (d); p = 0.00021 (e). f, g H&E and eMyHC staining of the TA muscles post the 3rd round injury. Scale bar: 50 μm. p = 0.00015, 0.00087, 0.0063, 0.000074, 0.0089, 0.035, 0.0014, 0.00011, 0.00042 and 0.00071 (f); p = 0.000023 (g). h Pax7+ SCs per view were quantified on Ctrl and iKO TA muscles on uninjured or post the 3 rounds of injury. p = 0.96, 0.00011, 0.0000013, 0.000014, 0.00066, 0.45, 0.0023, 0.00017, 0.00032, 0.95, 0.0022, 0.00019 and 0.0012. i Schematic for engraftment assay. Created with BioRender.com. j IF staining of YFP (green) and Laminin (red) on the TA muscles 21 days after engraftment. Scale bar: 50 μm. n = 5 mice per group. p = 0.0000091. k Quantification of Myod+ SCs per view on Ctrl and iKO TA muscles post the 3 rounds of injury. p = 0.0000012, 0.0013, 0.0054, 0.000028, 0.041 and 0.0012. n = 5 mice per group for 3, 5, 7 days post the 1st injury and 30 days post the 1st, 2nd and 3rd injury and engraftment assay; n = 3 mice per group for 3, 5, 7 days post 2nd and 3rd injury. All the bar graphs are presented as mean ± SD, Student’s t test (two-tailed unpaired) was used to calculate the statistical significance (b–h, j, k): *p < 0.05, **p < 0.01, ***p < 0.001. n.s. no significance. Source data are provided as a Source Data file.