Figure 4. Muscle regeneration was inhibited in glucocorticoid treated mice.

Mice were treated with 0.9% saline drinking water supplemented with 100 ug/ml corticosterone starting from 3 days prior cardiotoxin injury until the mice were sacrificed. Tibialis anterior muscles from corticosterone treated and untreated wild-type mice were injected with 30 ul of 10 nM cardiotoxin. The tibialis anterior muscles were harvested at different time points as indicated after injury. (A) The muscles were fixed in 4% paraformaldehyde/PBS (pH 7.4) for 1 hour at 4°C, infiltrated sequentially with 10%, 20% and 30% sucrose, and embedded in O. C. T. solution. Six micrometers of cryosections were stained with hematoxylin and eosin. Bars: 300 um. (B) Total RNA was isolated from tibialis anterior muscles and reverse transcribed. Triplicate samples were subjected to quantitative PCR. GAPDH was used as an internal control. The relative abundance of genes of interest was calculated after normalization to GAPDH. Data from three independent experiments were presented as mean ± SD. Asterisk: p<0.05.