Serial (10 μm) transverse sections of the soleus mid-belly region were taken on a CM1850 cryostat (Leica Biosystems, Buffalo Grove, IL) and mounted on gelatin-coated glass slides. Immunohistochemistry (n = 6-8/group) was performed for determination of fiber cross-sectional area (fCSA) and fiber type distribution, as previously reported [25 (link),30 (link),31 (link)]. Antibodies used were as follows: rabbit anti-laminin (1:200; Thermo Scientific, Waltham, MA), rhodamine-conjugated goat anti-rabbit IgG (1:500), Alexa Fluor® 488 goat anti-mouse IgG (1:200), Alexa Fluor® 488 goat anti-mouse IgM (1:200) all from Life Technologies (Carlsbad, CA); and anti-MHC I (BA.D5), anti-MHC IIA (SC.71), anti-MHC IIB (BF.F3), and anti-MHC IIX (BF.35) obtained from the Developmental Studies Hybridoma Bank (Iowa City, IA). Image acquisition was performed on an Eclipse TE2000-S microscope (Nikon Instruments, Melville, NY) with the fiber type distribution and average fCSA determined, in a blinded manner by consensus of two investigators, from an analysis of 300–350 total fibers per animals with Image J (NIH).
Free full text: Click here