目的 观察A型肉毒素对家兔股二头肌的致萎缩作用。方法 以新西兰大耳白兔为实验对象，分别以大(6.0U)、中（3.0U）、小(1.0U) 3种剂量的A型肉毒素注射于一侧股二头肌，以另侧股二头肌注射同剂量生理盐水为对照，观察其致萎作用的效果及持续时间，并在显微镜下观察股二头肌的形态学变化。结果 家兔股二头肌局部注射A型肉毒素14d后，可观察到明显的肌肉萎缩，28d后肌肉萎缩稳定，且以6.0U剂量组效果最佳。形态学观察显示：单个肌纤维直径变小，肌纤维融合，边界不清晰，排列不规则，粗纤维/细纤维比值变小；肌束间间隙增宽，数量增加；细胞核增多、聚集，核与核之间距离缩小。结论 局部肌肉注射A型肉毒素致萎效果好，模型稳定，是一种较为理想的单个目的肌肌萎缩造模方法。Objective: Observation on the effect of botulinum toxin type A cause biceps femoris atrophy in rabbits. Methods: Use New Zealand white big-ear rabbits as the laboratory animals, inject three different doses of botulinum toxin type A which is high(6.0U), medium(3.0U), low(1.0U) into one side of biceps femoris, the other side inject the same dose of normal saline to compare. Observe the effect of atrophy and duration time. Use microscope to observe the morphological change of biceps femoris. Results: After inject botulinum toxin type A 14 days, there is significantly atrophy. After 28 days, muscular atrophy is stable. Morphological observation indected that single muscle fiber diameter becomes smaller, muscle fibers fusion and boundary is not clear, arrange irregularly, crude fiber and fine fiber ratio decreased; muscle bundle gap widened and the nunber of it increase; unclear cole increased and aggregated, distance between unclears decrease. Conclusion: Locally injected botulinum toxin type A into the muscles had good effect on causing biceps femoris atrophy in rabbits and the modle is stable. So it’s an ideal single muscle atrophy molding method
