Contractility of permeabilized rat vastus intermedius muscle fibres following high-fat, high-sucrose diet consumption

Ian C. Smith*, Curtis Ostertag, Jennifer J. O’reilly, Jaqueline L. Rios, Teja Klancic, Graham Z. Macdonald, Kelsey H. Collins, Raylene A. Reimer, Walter Herzog

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Obesity is a worldwide health concern associated with impaired physical function. It is not clear if contractile protein dysfunction contributes to the impairment of muscle function observed with obesity. The purpose of this study was to examine if diet-induced obesity affects contractile function of chemically permeabilized vastus intermedius fibres of male Sprague–Dawley rats expressing fast myosin heavy chain (MHC) IIa or slow MHC I. Rats consumed either a high-fat, high sucrose (HFHS) diet or a standard (CHOW) diet beginning as either weanlings (7-week duration: WEAN7 cohort, or 14-week duration: WEAN14 cohort) or young adults (12-week duration: ADULT12 cohort, 24-week duration: ADULT24 cohort). HFHS-fed rats had higher (P < 0.05) whole-body adiposity (derived from dual-energy X-ray absorptiometry) than CHOW-fed rats in all cohorts. Relative to CHOW diet groups, the HFHS diet was associated with impaired force production in (a) MHCIfibres in the ADULT24 cohort; and (b) MHC IIa fibres in the ADULT12 and ADULT24 cohorts combined. However, the HFHS diet did not significantly affect the Ca2+-sensitivity of force production, unloaded shortening velocity, or ratio of active force to active stiffness in any cohort. We conclude that diet-induced obesity can impair force output of permeabilized muscle fibres of adult rats. Novelty: • We assessed contractile function of permeabilized skeletal muscle fibres in a rat model of diet-induced obesity. • The high-fat, high-sucrose diet was associated with impaired force output of fibres expressing MHC I or MHC IIa in some cohorts of rats. • Other measures of contractile function were not significantly affected by diet.

Original languageEnglish
Pages (from-to)1389-1399
Number of pages11
JournalApplied Physiology, Nutrition and Metabolism
Volume46
Issue number11
Early online date17 Jun 2021
DOIs
Publication statusPublished - Jun 2021
Externally publishedYes

Keywords

  • Fibre type
  • Myosin
  • Obesity
  • Pre-clinical models
  • Skeletal muscle

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