Division of Clinical Physiology, Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
Unit of Clinical Physiology, Karolinska University Hospital, Stockholm, Sweden.
Muscle Nerve. 2021 Apr;63(4):586-592. doi: 10.1002/mus.27151. Epub 2021 Jan 15.
In adult males, cross-sectional area (CSA) for type II muscle fibers is generally larger than for type I fibers. In this cross-sectional study the aim was to compare sex-related CSAs of various muscle fiber types during childhood-to-adulthood transition.
Percutaneous biopsy samples were obtained from vastus lateralis in 10-y-old children (10 males and 5 females) and in young adults (9 males and 7 females). Fiber types were classified by myofibrillar ATPase and CSAs from NADH-dehydrogenase staining.
Type IIA were larger than type I fibers in adult males, but not in adult females or children (age x sex x fiber type, P < .002). When including all participants, body weight and sex explained 78% of the variation in type IIA CSA but only body weight contributed for type I.
Sex-specific patterns in CSA of the muscle fiber types appears to develop during the transition from childhood to adulthood.
在成年男性中，II 型肌纤维的横截面积（CSA）通常大于 I 型纤维。在这项横断面研究中，我们的目的是比较儿童到成年过渡期各种肌纤维类型的性别相关 CSA。
在 10 岁儿童（男性 10 名，女性 5 名）和年轻成年人（男性 9 名，女性 7 名）的股外侧进行经皮活检。通过肌球蛋白 ATP 酶和 NADH 脱氢酶染色对纤维类型进行分类。
成年男性的 IIA 型纤维比 I 型纤维大，但成年女性和儿童则不然（年龄 x 性别 x 纤维类型，P <.002）。当包括所有参与者时，体重和性别解释了 IIA 型 CSA 变化的 78%，但只有体重对 I 型有贡献。
从儿童到成年的过渡期间，肌肉纤维类型的 CSA 出现了性别特异性模式。
