A Expression of HDAC4 mRNA at different time points in damaged muscle. TA muscles in 8-week-old C57BL/6 male mice (eight mice) were untreated (0 day), treated with saline (left leg) or cardiotoxin (CTX) (right leg) and muscles were harvested at indicated time points. Columns, mean of PCR duplicates. n = 1 for each time point.
B Expression of HDAC4 protein in damaged muscle. TA muscles in 8-week-old C57BL/6 male mice (8 mice) were untreated (0 day), treated with saline (left leg) or CTX (right leg) and muscles were harvested at indicated time points. n = 1 for each time point.
C Effect of SC-specific HDAC4 KO on populations of activated SCs by FACS analysis. TA and GA muscles in mice treated with tamoxifen (Tmx) were injured by CTX treatment for 2–3 days. Columns, mean; bars, SD of nine (SCs) or four (non-zs) independent experiments. *P < 0.05, ***P < 0.001 versus control KO+CTX (unpaired Student’s t-test).
D–F Effects of HDAC4 KO on the number of activated SCs expressing Pax7 or MyoD. TA muscles in 7-week-old male mice were stained with indicated antibodies. Note that SCs expressing low levels of Pax7 were also counted as positive (white arrow). Field means a grid (250 × 250 μm). Approximately 40 grids per muscle were counted. Scale bar: 400 μm. Columns, mean; bars, SEM. n = 3 for each group. *P < 0.05, **P < 0.01 versus control KO+CTX (unpaired Student’s t-test).
G mRNA expression of genes in regenerating muscle. TA muscles in 7-week-old male mice were used. Columns, mean; bars, SEM. n = 4 for each group. **P < 0.01, ***P < 0.001; NS, not significant, P > 0.05 (unpaired Student’s t-test).