Expression of MHC II decreased in old Gas7-deficient soleus while MHC I expression increased.

<p>Myofiber subtypes in the soleus or EDL of the 12 months old wild-type and Gas7-deficient mice were determined by anti-MHC I (slow muscle fiber) and anti-MHC II (fast muscle fiber) subtype-specific antibodies. (A) Levels of MHC II expression in soleus from Gas7-deficient (MT) mice were lower than wild-type (WT) and heterozygous (HT) groups (n = 4). (B) In EDL, no significant difference between Gas7 wild-type (WT), heterozygous (HT), and deficient (MT) mice was observed. Protein extract (2 µg), separated by NuPAGE on 3–8% gels (Invitrogen), was transferred to PVDF membranes and probed with specific antibody for MHC I (NOQ7.5.4D, Sigma) and MHC II (My32 antibody, Sigma). Internal control lanes were probed with anti-actin antibody (Chemicon) on the same membrane. (C) and (D) show histograms based on densitometry of the Western blot signals shown in (A) and (B). Levels of both types of MHC were normalized to actin (internal control) in soleus and EDL. Mean ± SEM, ***<i>P</i><0.001, *<i>P</i><0.05. (E) Body weight and weight of soleus and EDL muscle of Gas7 wild-type (WT), heterozygous (HT) and deficient (MT) mice.