Figure 5. Total ubiquitin levels in adult and old rats after hindlimb unloading (HU) and reloading. Representative Western blot and quantification of total ubiquitin levels in the soleus (A) and tibialis anterior (TA) (B) muscles of adult (9 mo, open squares) and old (29 mo, filled squares) rats after 14 days of HU and after 3, 7, and 14 days of reloading. Total protein, determined by stain-free imaging of the PVDF membrane, was used to normalize protein expression. Data are expressed as a percentage relative to the adult control group (n=5-6/group). Values are mean ± SEM, *p<0.05 vs adult control, #p<0.05 vs old control, φp<0.05 vs adult at same time point.