The intensity of microcurrent therapy is important in the treatment of muscle damage. In one study, when an intensity of 100–500μA was applied after muscle damage, the healing process, including amino acid transport, triphosphate generation, and protein synthesis, increased by 30–40% above the control level. On the contrary, when the intensity exceeded 1000μA, these biostimulatory effects were reversed. Therefore, we aims to investigate the regenerative effect of microcurrent electric stimulation according to intensity on gastrocnemius (GCM) muscle atrophy in rabbits induced by cast immobilization

Fifteen male New Zealand white rabbits were randomly allocated into 3 groups of 5 rabbits. Right GCM muscle was used for immobilization by cast for 2 weeks (IC). IC (group 1), IC and Microcurrent stimulation (MS: 25μA) for 2 weeks after CR (group 2), and IC and Microcurrent stimulation (MS: 5000μA) for 2 weeks after CR (group 3). Atrophic change of Rt. calf circumference, Compound muscle action potential (CMAP) of Rt. tibial nerve, thickness of Rt. GCM by ultrasound was calculated. Muscle composition of GCM muscle and cross sectional area (CSA) of muscle fibers was measured. Proliferating cell nuclear antigen (PCNA) and bromodeoxyuridine (BrdU) positive cell ratio was calculated as the number of BrdU positive cells per muscle fiber.

Mean atrophic changes of Rt. calf circumference, amplitude of CMAP on Rt. tibial nerve, and Rt. medial and lateral GCM muscle thickness in group 2 was significantly lesser than those in group 1 and 3 (P<.05). Mean CSA of medial GCM type 1 muscle fibers and PCNA and BrdU ratio in group 2 were significantly greater than those in group 1 and group 3, respectively (P<.05).

The result shows that a low-intensity microcurrent promotes more effectively than high-intensity in regeneration of GCM type 1 muscle atrophy.