Kirkeby S, Garbarsch C
Department of Oral Function and Physiology, Faculty of Health Sciences, University of Copenhagen, Denmark.
Histol Histopathol. 2000 Jan;15(1):61-71. doi: 10.14670/HH-15.61.
This study is an attempt to objectively evaluate age-related changes in human muscles by use of histomorphometric methods. Aging in humans induces dramatic transformations in the skeletal muscles but little is known as to whether or not the aging processes per se may affect all muscles equally. In this study aging of two human muscles with different functions, origin and nerve supply is compared. Sections were cut from masseter and vastus lateralis muscles obtained from young adults aged 18-24 years and from the very old aged 90-102 years. Muscle fiber types were classified with the traditional myofibrillar ATPase staining. Various histomorphometric parameters of the different fiber types in human masseter and vastus lateralis muscle sections were obtained by image analyses to evaluate the age-related changes in the muscle fibers. The following variables were calculated: the number of each fiber type per photographed area; the area of each fiber and two indicators for the shape of the muscle fibers. In the aging muscles there was no relative preferential loss of a fiber type. High numbers of intermediate ATPase-stained fibers (IM fibers) were found in some old vastus muscles but were only sporadic in young vastus muscles. However, there was no change in the percentage distribution of intermediate ATPase-stained fibers when young and very old human masseter muscles were compared. Incubation of the sections with antimyosin antibodies showed that the IM fibers in old masseter and old vastus contained different myosin heavy chains. Thus ATPase activity and anti-myosin staining displayed a somewhat different pattern of fiber type distribution. The main changes in the shape and area indicated that type I fibers in the masseter became more circular while in the vastus they decreased significantly in size. The type II fibers in the vastus became very small and deviated significantly from circularity whereas the type II fibers in the masseter only exhibited a decrease in the size of the fibers. Histomorphometric measurements show that aging affects different human muscles in various ways.
本研究旨在尝试通过组织形态计量学方法客观评估人类肌肉中与年龄相关的变化。人类衰老会导致骨骼肌发生巨大变化，但对于衰老过程本身是否会对所有肌肉产生同等影响，人们知之甚少。在本研究中，对具有不同功能、起源和神经支配的两块人类肌肉的衰老情况进行了比较。切片取自18 - 24岁的年轻成年人以及90 - 102岁的高龄老人的咬肌和股外侧肌。采用传统的肌原纤维ATP酶染色对肌纤维类型进行分类。通过图像分析获得人类咬肌和股外侧肌切片中不同纤维类型的各种组织形态计量学参数，以评估肌纤维中与年龄相关的变化。计算了以下变量：每个拍摄区域内每种纤维类型的数量；每条纤维的面积以及两个用于表示肌纤维形状的指标。在衰老的肌肉中，没有一种纤维类型出现相对优先的丢失。在一些老年股外侧肌中发现大量中间ATP酶染色纤维（IM纤维），但在年轻股外侧肌中仅为散在分布。然而，比较年轻和高龄人类咬肌时，中间ATP酶染色纤维的百分比分布没有变化。用抗肌球蛋白抗体孵育切片显示，老年咬肌和老年股外侧肌中的IM纤维含有不同的肌球蛋白重链。因此，ATP酶活性和抗肌球蛋白染色显示出略有不同的纤维类型分布模式。形状和面积的主要变化表明，咬肌中的I型纤维变得更圆，而股外侧肌中的I型纤维尺寸显著减小。股外侧肌中的II型纤维变得非常小，且明显偏离圆形，而咬肌中的II型纤维仅表现出纤维尺寸减小。组织形态计量学测量表明，衰老以多种方式影响不同的人类肌肉。
