Electrical stimulation protocol to maintain mass and contractile force in denervated muscles

Due to atrophy, rat EDL muscles denervated for 1 month have a mass of only 38% of contralateral control muscles, and at 2 months it is down to 32%. Likewise, contractile force at 1 month is only 6% and at 2 months it is down to 2% of control values. Chronic electrical stimulation maintains both the muscle's mass and contractile force at some percent of control values depending on the protocol used. We tested a stimulation protocol resembling the bursts of activity followed by periods of rest observed in animal behavior. We tested 2 protocols producing either 100 or 300 muscle contractions per day. EDL muscles of Wistar rats were denervated and stimulated for 5 weeks. The muscle's mass and force were significantly different between the two groups. The 300 contractions/day protocol maintained both muscle mass and force above 80% of control values, whereas with 100 contractions/day the values did not differ significantly from unstimulated muscles.