AUTHOR=Murray Jason D., Canan Ben D., Martin Christopher D., Stangland Jenna E., Rastogi Neha , Rafael-Fortney Jill A., Janssen Paul M.

TITLE=The force-temperature relationship in healthy and dystrophic mouse diaphragm; implications for translational study design

JOURNAL=Frontiers in Physiology

VOLUME=Volume 3 - 2012

YEAR=2012

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2012.00422

DOI=10.3389/fphys.2012.00422

ISSN=1664-042X

ABSTRACT=In the field of muscular dystrophy, striated muscle function is often assessed in vitro in dystrophin-deficient mdx mice in order to test the impact of a potential treatment strategy.  Although many past studies have assessed diaphragm contractile function at or near room temperature, the diaphragm performs in vivo at 37ºC.  To improve translation of bench-top results to possible clinical application, we studied temperature-dependence of contractile performance in wild-type (C57BL/10) and mdx muscle strips at temperatures from 25 to 37ºC.  Maximal tetanic force in wild-type muscles was higher at 37 ºC (198±11 vs. 155±9 mN/mm2 at 25ºC), while the difference between wild-type and mdx was extremely similar: wild-type muscles produced 45.9% and 45.1% more force at 25 and 37ºC respectively.  At 37ºC twitch contraction kinetics and 50% rise time to tetanic plateau were slower in mdx diaphragm.  A fatigue/injury protocol indicated two-fold fatigue/contraction induced force deficit in mdx muscles.  We conclude that assessment of diaphragm muscle strips can be reliably and reproducibly performed at 37 ºC.