Open AccessInfluence of longitudinal radiation exposure from microcomputed tomography scanning on skeletal muscle function and metabolic activity in female CD ‐1 mice
Author(s) -
Mikhaeil John S.,
Sacco Sandra M.,
Saint Caitlin,
Gittings William,
Bunda Jordan,
Giles Cameron R.,
Andrew Fajardo Val,
Vandenboom Rene,
Ward Wendy E.,
LeBlanc Paul J.
Publication year - 2017
Publication title -
physiological reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.918
H-Index - 39
ISSN - 2051-817X
DOI - 10.14814/phy2.13338
Subject(s) - isometric exercise , in vivo , hindlimb , skeletal muscle , endocrinology , medicine , chemistry , anatomy , biology , microbiology and biotechnology
Microcomputed tomography ( μ CT ) is an imaging technology to assess bone microarchitecture, a determinant of bone strength. When measured in vivo, μ CT exposes the skeletal site of interest to a dose of radiation, in addition to nearby skeletal muscles as well. Therefore, the aim of this study was to determine the effects of repeated radiation exposure from in vivo μ CT on muscle health – specifically, muscle morphometrics, contractile function, and enzyme activity. This study exposed the right hind limb of female mice to either a low (26 cG y) or moderate (46 cG y) dose, at 2, 4, and 6 months of age, while the left hind limb of the same animal was exposed to a single dose at 6 months to serve as a nonirradiated control. Muscle weight, cross‐sectional area, isometric contractile function, and representative maximal enzyme activities of amino acid, fatty acid, glucose, and oxidative metabolism in extensor digitorum longus ( EDL ) and soleus were assessed. Low‐dose radiation had no effect. In contrast, moderate‐dose radiation resulted in a 5% increase in time‐to‐peak tension and 16% increase in half‐relaxation time of isometric twitches in EDL , although these changes were not seen when normalized to force. Moderate‐dose radiation also resulted in an ~33% decrease in citrate synthase activity in soleus but not EDL , with no changes to the other enzymes measured. Thus, three low doses of radiation over 6 months had no effect on contractile function or metabolic enzyme activity in soleus and EDL of female mice. In contrast, three moderate doses of radiation over 6 months induced some effects on metabolic enzyme activity in soleus but not EDL . Future studies that wish to investigate muscle tissue that is adjacent to scanned bone should take radiation exposure dose into consideration.