Fig. 9.

Effect of hindlimb unloading (HU) on HDAC4 and Gadd45a expression in adult and old rats. mRNA expression of HDAC4 and Gadd45a was assessed by quantitative PCR in the soleus (A), medial gastrocnemius (MG; B), and tibialis anterior (TA; C) muscles of adult (9 mo, □) and old (29 mo, ■) rats after 3, 7, and 14 days of HU. Gene expression was normalized to tissue weight. Data are expressed as a fold change relative to the adult control group (n = 5–6/group). Values are means ± SE. *P < 0.05 vs. adult control. ^#P < 0.05 vs. old control. ^ϕP < 0.05 vs. adult at same time point.