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

Figure 5

Morphology of neuromuscular junctions (NMJs) at different time points after contusion. Postsynaptic NMJ was identified by rhodamine α-bungarotoxin staining for acetylcholine receptors (AChRs) and observed by confocal microscopy. Representative confocal photomicrographs of NMJ (scale scar: 20 μm) displayed the differences among all groups following contusion (a). In normal muscle fibers, AChR clusters were organized in a classical pretzel-shaped structure. NMJs showed a frequent fragmented appearance on day 7 after contusion: AChR staining in muscles was generally dramatically disorganized, with its branches barely discernable. On the 14th and 28th day, NMJs appeared to have some branches and be less fragmented, and the size of the postsynaptic apparatus had increased. Quantitative analysis of NMJs revealed that the mean stained area (b) increased and discontinuities (c) of NMJs decreased gradually during repair. The treatment (EA-Ashi, EA-ST36, and EA-AS) increased mean stained area and reduced discontinuity of NMJs compared to contusion. EA-ST36 decreased more discontinuity (P < 0.05), especially at the second and third week, and EA-Ashi was more effective during the first two weeks on enhancing mean stained area of NMJs, by comparison (P < 0.05) (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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