Effect of Combination Microcurrent Electrical Neuromuscular Stimulation and Hyperbaric Oxygen Therapy on the Regeneration of Injured Skeletal Muscle in Mice

Abstract

We investigated, in an animal model of skeletal muscle injury, whether microcurrent electrical neuromuscular stimulation (MENS) and hyperbaric oxygen (HBO) therapy used in combination (MENS and HBO) enhances the restorative benefits conferred by these treatments alone. Skeletal muscle injury was simulated in 40 7-week-old male C57BL/6J mice by injection of cardiotoxin (CTX) into the left tibialis anterior (TA) muscle of each mouse, which induced the necrosis-regeneration cycle. The mice were divided into 4 groups of 10 each and subjected to one of the following no additional treatment (X), HBO (XH), MENS (XM), MENS and HBO (XMH) groups. MENS was delivered at 10 µA intensity, 0.3 Hz frequency, and 250 msec pulse width for 60 minutes per day, 3 days per week for 2 weeks, and HBO was performed with 100% oxygen at 2 atmospheres absolute (ATA) for 60 minutes per day, 3 days per week for 2 weeks. One and 2 weeks after CTX injection, the TA muscle was dissected. Two weeks after CTX injection, both the mean fiber cross-sectional area (CSA) and percentage increase in the fiber CSA were significantly greater in the XMH group than in the X group (P <0.05). The fiber CSA increased without treatment and also under sole treatment with either MENS or HBO, but the values did not differ significantly. Our data indicate that combination MENS and HBO therapy enhances regeneration of injured skeletal muscle and that such combination therapy may be clinically beneficial.