Lumican expression in skeletal muscles in various mouse models. (A,B) Body composition parameters, including body weight and muscle mass, were determined in young and old mice (n = 5 per group) (A) and in exercised and unloading mice (n = 5 per group). (B). Experimental mouse models are described in the Materials and Methods. Relative muscle mass is expressed as the percentage of body weight. (C,D) Expression levels of lumican mRNA were measured by real-time PCR in muscles of young and old mice (C) and exercised and unloading mice (D). Each bar represents the mean ± standard error of the mean (SEM). * p < 0.05 between the two groups. NS, not significant. GC, gastrocnemius. SOL, soleus. TA, tibialis anterior. EDL, extensor digitorum longus.