Hu Shao-nan, Xu Jian-guang, Gu Yu-dong, Li Ji-feng
Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, P. R. China 200040.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2002 Jan;16(1):44-7.
To observe the ultrastructural changes and number of satellite cells in different muscles with different denervation interval and investigate the mechanism of denervation atrophy.
Muscles of different denervation interval were harvested, which were 6 biceps brachii and 6 abductor digiti minimi. The ultrastructure of the samples were observed under transmission electron microscope. The number of nucleus and satellite cells were counted to calculate the percentage content of satellite cells.
In early stage of denervation, the myofilament and sarcomere of the majority were well oriented. The nucleoli of some muscle cell nucleus were enlarged and pale. Vacuolarization was also seen in some mitochondria. There was no obvious proliferation of collagen fiber around myofibers. After denervation of half a year, rupture and disorientation of myofilament was seen. The nucleus became smaller, dark stained, and some of them were condensed. There was proliferation of fibroblasts, adipose cells and collagen fibers around myofibers. Motor endplate was not recognized one year after denervation. In the early stage of denervation, satellite cell percentage of the two muscles was relatively high. It then declined with time. One year after denervation, satellite cells were scarcely detected. Comparison of the curves for satellite cell declination in two muscles revealed that the declination of the abductor digiti minimi was faster than that of biceps brachii. Decrease of the former started 3 months after denervation, while the latter started after 6 months.
Disappearing of motor endplate and proliferation of collagen fibers are main factors that affect the treatment outcome in late cases. Decrease of satellite cell number is another cause. The correlation of less satellite cell in abductor digiti minimi and poorer recovery of hand intrinsic muscles indicates that increment of satellite cells in long-term denervated muscles may be one of the effective measures to improve treatment outcome.
观察不同失神经支配时间的不同肌肉中卫星细胞的超微结构变化及数量，探讨失神经萎缩的机制。
取不同失神经支配时间的肌肉，其中肱二头肌6例，小指展肌6例。样本的超微结构在透射电子显微镜下观察。计数细胞核和卫星细胞的数量，计算卫星细胞的百分比含量。
失神经早期，多数肌丝和肌节排列良好。部分肌细胞核仁增大、变淡。部分线粒体可见空泡化。肌纤维周围未见明显胶原纤维增生。失神经半年后，可见肌丝断裂、排列紊乱。细胞核变小、深染，部分细胞核浓缩。肌纤维周围有成纤维细胞、脂肪细胞和胶原纤维增生。失神经1年后未见到运动终板。失神经早期，两种肌肉的卫星细胞百分比相对较高。随后随时间下降。失神经1年后，几乎检测不到卫星细胞。比较两种肌肉卫星细胞下降曲线发现，小指展肌的下降速度比肱二头肌快。前者在失神经3个月后开始下降，而后者在6个月后开始下降。
运动终板消失和胶原纤维增生是影响晚期病例治疗效果的主要因素。卫星细胞数量减少是另一个原因。小指展肌卫星细胞较少与手部固有肌恢复较差的相关性表明，长期失神经肌肉中卫星细胞的增加可能是改善治疗效果的有效措施之一。
