Electrical impedance myography: transitioning from human to animal studies.
OBJECTIVE
To determine the feasibility of performing electrical impedance myography (EIM) in rats.


METHODS
EIM was performed on the hamstring muscles of 6 healthy adult rats with applied frequencies of 2-300 kHz. Studies were performed over a 6-week period, with 3 rats having recordings made from the skin (surface EIM) and 3 with recordings directly from the muscle (direct-muscle EIM). In addition, sciatic nerve crush was performed on one rat and comparisons made pre- and post-injury. Reactance and resistance were measured and the primary outcome variable, the phase angle (theta), calculated.


RESULTS
EIM patterns in the rat hamstring muscles were qualitatively similar to those observed in human subjects. This held true for both surface and direct-muscle recordings, although direct-muscle data appeared less repeatable. Sciatic nerve crush data in the single rat showed a dramatic reduction in phase and a relative loss of frequency-dependence.


CONCLUSIONS
EIM data similar to that obtained from human subjects can be acquired from rat muscles with surface recordings proving more consistent and easier to obtain than direct-muscle recordings. Changes seen with sciatic nerve crush mirror those seen in patients with neurogenic injury.


CONCLUSIONS
These results support the possibility of performing EIM on rat models of neuromuscular disease.
Nie
Rui
R
Department of Neurology, Division of Neuromuscular Diseases, Harvard Medical School, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, TCC 810, Boston, MA 02215, USA.
Sunmonu
N Abimbola
NA
Chin
Anne B
AB
Lee
Kyungmouk S
KS
Rutkove
Seward B
SB
D000818:Animals; D017097:Electric Impedance; D004566:Electrodes; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D009213:Myography; D009409:Nerve Crush; D009468:Neuromuscular Diseases / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries