ABSTRACT
Objective To observe the effect of different interventions on muscle healing following contusion by electromyographical signal, and functionally to study the significance of electromyographical technique in evaluating the healing quality of skeletal muscle after injuries. Methods A standard contusion model was developed at the right gastrocnemius by specific device in 108 male rats. The animals were divided into three groups:group IGF-1,local injection by exogenous IGF-1 at injured site; group Chinese medicine treated with the injection of Huangqidanshen, and group natural healing for control. EMG signals of gastrocnemius, such as fibrillation potentials, positive sharp waves as well as the latency and wave-amplitude of compound muscle action potentials (CMAPs) were probed, recorded and compared at day 2、5、7、10、14、21、28、35 and 56 after injury respectively. Results (1) Fibrillation potentials and positive sharp waves were discovered at day 2 to 5 after contusion, and reached its peak by day 7 to 10, and then normalized gradually around the 35th day with muscle healing in group natural healing. Above abnormal signals disappeared much more early in group IGF-1, then that in group Chinese medicine. (2) The latency and wave-amplitude of CMAP shown a gradual recovery process with muscle healing. The recovery tendency was most rapid in group IGF-1, slower in group Chinese medicine, and latest in group natural healing. (3) The wave-amplitude of CMAP approached to normal in group IGF-1 by 8 weeks following contusion, a little bit later in group Chinese medicine groups, and lastly in group natural healing. Conclusions(1) Electromyographical study verified that IGF-1 and Huangqidanshen could improve healing and functional recovery following muscle injury. IGF-1 was a much more strong intervention for healing promotion. (2) EMG is an useful tool in evaluating the healing process and healing quality of skeletal muscle.