I'm planning to excise mouse muscle to use for ex vivo mechanical testing. What is the best way to prevent the stiffening effects of rigor mortis from confounding results if I cannot isolate the tissue immediately before the testing? Can the muscle be stored in PBS on ice or possibly in media for an hour or so with minimal effects? Thank you
Rigor mortis doesn't happen that fast but an isolated muscle can easily die on you if not taken care of. If the isolated muscle cannot be studied immediately, it should be bathed in ice cold Krebs-Ringer oxygenated with 95% O2:5% CO2. The muscle should be kept at close to physiological length. Also remember that if you plan to study the muscle ex vivo at physiological temperatures (~37 oC), muscle size is limited to 30 mg (S.S. Segal & J.A. Faulkner, Am J Physiol 248:C265-270, 1985).
May I further comment that studying thin muscles can help you avoid having a muscle with a 'hypoxic' or even a 'rigor' core.