Effects of Zusanli and Ashi Acupoint Electroacupuncture on Repair of Skeletal Muscle and Neuromuscular Junction in a Rabbit Gastrocnemius Contusion Model

Figure 3

Tissue sections were stained with hematoxylin and eosin (HE) to evaluate the general morphology of muscle fibers. HE staining (×200) of normal skeletal muscle revealed fibers uniform in size containing peripherally located nuclei. After contusion, there was skeletal muscle degeneration and necrosis characterized by variation in the size and shape of skeletal muscle fibers, granular and/or hyalinized eosinophilic cytoplasm. Enhanced mononuclear cell infiltration was detected in the connective tissue between muscle fibers. Over time, regenerating myofibers that are centrally nucleated and heterogeneous in size could be detected. By day 28 after contusion, some regenerating fibers were mature, especially in the group receiving EA-AS, peripherally nucleated, and homogeneous in size (a). Quantitative analyses of the number (b) and average diameter (c) of skeletal muscle fibers were administrated on the 7th, 14th, and 28th day after contusion. Compared to the untreated group (contusion), the treatment groups (EA-Ashi, EA-ST36, and EA-AS) showed an increase in number and average diameter of myofibers (P < 0.05). EA-ST36 increased more myofiber number especially from two weeks (P < 0.05) and EA-Ashi was more effective on enhancing average diameter of myofibers (P < 0.05) by comparison between them (EA-Ashi versus EA-ST36, ^▲P < 0.05; EA-AS versus EA-Ashi and EA-ST36, ^#P < 0.05; contusion group versus treatment groups, ^★P < 0.05; EA-Ashi, electroacupuncture at Ashi acupoints; EA-ST36, electroacupuncture at ST36; EA-AS, electroacupuncture at Ashi acupoints and ST36; treatment groups (EA-Ashi, EA-ST36, and EA-AS)).

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(b)

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