Lexell J, Downham D Y
Department of Neurology, University of Umeå, Sweden.
Acta Neuropathol. 1991;81(4):377-81. doi: 10.1007/BF00293457.
Methods that objectively assess the muscle fibre-type arrangement may improve the detection of fibre-type grouping, a diagnostic sign of a denervation and reinnervation process. To distinguish between a diseased and a normal muscle, there is a need for quantitative data on the fibre-type arrangement in healthy human muscles at different ages. In this study, cross-sections were prepared of whole autopsied vastus lateralis muscle from 24 previously physically healthy men, aged 15 to 83 years. The arrangements of type 1 and type 2 fibers were assessed in terms of the number of enclosed fibres in individual fascicles throughout each muscle. Recent improvements to the enclosed fibre method were used to define measures of randomness which facilitated the combination of several sample areas and the quantification of the fibre-type arrangements. Segregation was typical for young muscles, randomness was most common between 30 and 50 years of age, while some fibre-type grouping was considered "normal" in old muscles. The arrangements of type 1 and type 2 fibres were quantitatively similar, irrespective of the age of the individual. The results imply that the fibre population changes considerably during a lifetime, and that it undergoes a continuous denervation and reinnervation process with normal ageing. Because of its importance, age should be accommodated in the analysis of a muscle sample, irrespective of the statistical model and method used.
客观评估肌纤维类型排列的方法可能会改善对纤维类型分组的检测，而纤维类型分组是去神经和再支配过程的诊断标志。为了区分患病肌肉和正常肌肉，需要获取不同年龄健康人肌肉中纤维类型排列的定量数据。在本研究中，对24名年龄在15至83岁、生前身体健康的男性尸检后的完整外侧股四头肌制备了横断面。根据每块肌肉中各个肌束内封闭纤维的数量评估1型和2型纤维的排列。采用封闭纤维法的最新改进来定义随机性指标，这有助于合并多个样本区域并对纤维类型排列进行量化。在年轻肌肉中，分离是典型特征；在30至50岁之间，随机性最为常见；而在老年肌肉中，一些纤维类型分组被认为是“正常的”。无论个体年龄如何，1型和2型纤维的排列在数量上是相似的。结果表明，纤维群体在一生中会发生显著变化，并且随着正常衰老会经历持续的去神经和再支配过程。由于其重要性，在分析肌肉样本时应考虑年龄因素，无论使用何种统计模型和方法。
