Body mass (mean+sem) for <i>Mstn</i>(−/−) and wild-type mice during seven days of unloading followed by seven days of reloading (n = 6 per genotype and day).

<p>Unlike letters denote significant differences (<i>P</i>&lt;0.05) across days (independent of genotype).</p

Arbitrary concentrations (mean+sem) of MyoD, Myf5 and Myogenin mRNA in the <i>B. femoris</i> muscles of <i>Mstn</i>(−/−) and wild-type mice during seven days of unloading and seven days of reloading (n = 6 per genotype and day).

<p>Asterisks denote differences between genotypes on days shown (*<i>P</i>&lt;0.05, **<i>P</i>&lt;0.01 and ***<i>P</i>&lt;0.001). Unlike letters denote significant differences (<i>P</i>&lt;0.05) across days (independent of genotype).</p

The amount of 4E-BP1 bound to eIF4E.

<p>(A) Representative western blots of 4E-BP1 bound to eIF4E and (B) the ratio (mean+sem) of 4E-BP1 bound to isolated eIF4E purified by an m⁷GTP-sepharose pull-down assay in the <i>gastrocnemius</i> muscle of <i>Mstn</i>(−/−) and wild-type mice (n = 6 per genotype and day) before and after two days of unloading. There were main effects of day (<i>P</i>&lt;0.05) and genotype (<i>P</i>&lt;0.05), but no day × genotype interaction.</p

Changes in the composition of MyHC and the cross-sectional area of muscle fibres.

<p>(A) Representative gels stained with coomassie blue showing the myosin heavy chain (MyHC) protein isoforms in the <i>B. femoris</i> muscle of <i>Mstn</i>(−/−) and wild-type mice during seven days of unloading and seven days of reloading. A mixture of 1∶1 <i>soleus</i> and <i>Extensor digitorum longus</i> served as a ladder. (B) The change (mean+sem) in the relative abundance of type IIb MyHC protein in the <i>B. femoris</i> muscles is shown for <i>Mstn</i>(−/−) and wild-type mice (n = 6 per genotype and day) during seven days of unloading and seven days of reloading. There were main effects of day (<i>P</i>&lt;0.001) and genotype (<i>P</i>&lt;0.01), but no day×genotype interaction. Asterisks denote significant differences between genotypes (*<i>P</i>&lt;0.05, **<i>P</i>&lt;0.01). (C) Cross-sectional area (mean+sem) of myofibres in the <i>gastrocnemius</i> muscle of <i>Mstn</i>(−/−) and wild-type mice during seven days of unloading and seven days of reloading. The cross-sectional area was significantly reduced in both genotypes at d7 (P&lt;0.05), before being restored to pre-unloading areas at d14. Asterisks denote significant differences between genotypes (***<i>P</i>&lt;0.001). Unlike letters denote significant differences (<i>P</i>&lt;0.05) across days (independent of genotype).</p

Arbitrary concentrations (mean+sem) of LC3b, Gabarapl1 and Atg4b mRNA in the <i>B. femoris</i> muscles of <i>Mstn</i>(−/−) and wild-type mice during seven days of unloading and seven days of reloading (n = 6 per genotype and day).

<p>The asterisks denote differences between genotypes on days shown (**<i>P</i>&lt;0.01, ***<i>P</i>&lt;0.01). Unlike letters denote significant differences (<i>P</i>&lt;0.05) across days (independent of genotype).</p

Muscle mass (mean+sem) expressed as a percent of the initial body mass at d0 for <i>Mstn</i>(−/−) and wild-type mice at days 0, 2 and 7 of unloading and days 8, 10 and 14 of reloading.

<p>The asterisks denote differences from d0 within genotype at the days noted (*<i>P</i>&lt;0.05, **<i>P</i>&lt;0.01 and ***<i>P</i>&lt;0.001). The asterisks (**<i>P</i>&lt;0.01) in the data for soleus indicates that muscle mass has been lost equally from both genotypes at d7. EDL = <i>Extensor digitorum longus</i>, Gast = <i>gastrocnemius</i>, Quad = <i>Quadriceps femoris</i>.</p