Effects of chronic high-fat feeding on skeletal muscle mass and function in middle-aged mice
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Background and aims
Increased adipose tissue may promote catabolic events in skeletal muscle. The aim of this study was to test whether high-fat diet (HFD)-induced obesity would accelerate the onset of muscle wasting in middle-aged mice.
Muscle was collected from C57BL/6 mice at 9 months of age (baseline) and 14 months of age after consuming a control (C) or HFD. Mice in C and HFD were also subjected to evaluations of body composition and function before and after their respective diets.
HFD demonstrated significant (p < 0.05) losses of grip strength (−15 %) and sensorimotor coordination (−11 %), whereas C did not. Lean mass decreased to a greater degree in HFD although not significantly (C: −20.69 ± 7.94 vs. HFD: −31.14 ± 5.49 %, p > 0.05). Gastrocnemius, quadriceps, and hamstrings mass in C and HFD were significantly reduced from baseline (−27 to 43 and −39 to 47 %, respectively, p < 0.05) with no differences between the two; however, soleus mass was lower only in HFD (−24 %, p = 0.03). Myofiber area, satellite cells, and myonuclei of the gastrocnemius were lower only in HFD (−23, −19, and −16 %, respectively, p < 0.05) compared to baseline.
HFD-induced obesity adversely affected function in middle-aged mice. Atrophy of the soleus in HFD but not C suggests sensitivity of oxidative muscle to HFD-dependent catabolism more so than aging. In the muscles containing fast/mixed fibers, aging effects may have concealed the catabolic nature of HFD; however, morphological changes in the gastrocnemius including decreased fiber area, satellite cells, and myonuclei are consistent with an atrophic phenotype related to HFD.
KeywordsAging High-fat diet Obesity Functionality Body composition
The authors acknowledge the efforts of Dr. Samuel C. Grant, Dr. Bahram H. Arjmandi, Dr. Paul C. Henning, and Dr. Chris Boehm for their technical assistance. This work was partially supported by Sekwang Inc., Florida State University, Vital Pharmaceuticals, and Ocean Nutrition.
Conflict of interest
The authors declare that they have no conflict of interest.