title: The force-temperature relationship in healthy and dystrophic mouse diaphragm; implications for translational study design.
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 37°C. 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°C to 37°C. Maximal tetanic force in wild-type muscles was higher at 37°C (198 ± 11 vs. 155 ± 9 mN/mm(2) at 25°C), while the difference between wild-type and mdx was extremely similar: wild-type muscles produced 45.9% and 45.1% more force at 25°C and 37°C respectively. At 37°C twitch contraction kinetics and 50% rise time to tetanic plateau were slower in mdx diaphragm. A fatigue/injury protocol indicated 2-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°C.
authors.affiliation: Department of Physiology and Cell Biology, The Ohio State University ,  Columbus, OH, USA.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Murray
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Canan
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Martin
authors.forename: Jenna E
authors.initials: JE
authors.lastname: Stangland
authors.forename: Neha
authors.initials: N
authors.lastname: Rastogi
authors.forename: Jill A
authors.initials: JA
authors.lastname: Rafael-Fortney
authors.forename: Paul M L
authors.initials: PM
authors.lastname: Janssen