Muscle and Nerve Responses After Different Intervals of Electrical Stimulation S

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Am J Phys Med Rehabil. 2008 Sep 10.

Muscle and Nerve Responses After Different Intervals of Electrical

Stimulation Sessions on Denervated Rat Muscle.

Lima SC, Caierão QM, Peviani SM, Russo TL, Somazz MC, Salvini TF,

Teodori RM, Minamoto VB.

Affiliations: Department of Physical Therapy (SCV, QMC, MCS, RMT,

VBM), Piracicaba Methodist University, Piracicaba; and Department of

Physical Therapy (SMP, TLR, TFS), São Federal University, São

, São o, Brazil.

Muscle and nerve responses after different intervals of electrical

stimulation sessions on denervated rat muscle.Electrical stimulation

is a procedure used to treat denervated muscles. The number of

electrical stimulation sessions varies across muscle rehabilitation

protocols, from daily to certain days throughout the week.

The purpose of this study was to evaluate how muscle and nerve

respond to different intervals of electrical stimulation applied to

denervated muscle. Denervation of rat gastrocnemius muscle was

imposed via nerve crush, and electrical stimulation was applied to

the muscle either daily (Monday through Friday) or on alternate days

(Monday, Wednesday, and Friday).

Four experimental groups were studied: denervated, denervated plus

daily electrical stimulation, denervated plus alternate-day

electrical stimulation, and control. On the 12th day after nerve

crush, levels of MyoD, myostatin, and atrogin-1 gene expression, as

well as muscle fiber and nerve morphometry, were evaluated.

Expression levels of all three genes were higher in the denervated

group when compared with control. Also, expression levels of MyoD and

myostatin were higher in denervated plus alternate-day electrical

stimulation and denervated plus daily electrical stimulation groups

when compared with denervated.

The denervated plus daily electrical stimulation group had lower

atrogin-1 expression, lower density of intramuscular connective

tissue, and better morphometric nerve characteristics when compared

with the denervated and denervated plus alternate-day electrical

stimulation.

These results indicate that the responses of both muscle and nerve to

electrical stimulation after muscle denervation depend on the

intervals of electrical stimulation application.