Revisiting the peculiar regional distribution of muscle fiber types in rat Sternomastoid Muscle

Basic and applied myology

Damiana Incendi¹  Tiziana Martinello⁴  Valerio Gobbo⁵  Andrea Porzionato⁸  Veronica Macchi⁹  Raffaele De Caro^1,10  Marco Patruno^1,10  Dario Coletti^1,11  Barbara Ravara^1,12 

[1] A&Department of Anatomy, Histology, Forensic Medicine &Department of Comparative Biomedicine and Food Science, University of Padova;Human Anatomy Section of the Department of Neurosciences, University of Padova;Interdepartmental Research Center of Myology (CIR-Myo), University of Padova;Interuniversity Institute of Myology, Italy;Orthopedics, School of Medicine Sapienza University of Rome, Italy;C M-C Foundation for Translational Myology, Padova;CNR Institute of Neuroscience, Padova;Human Anatomy Section of the Department of Neurosciences, University of Padova;Interdepartmental Research Center of Myology (CIR-Myo), University of Padova;Laboratory of Translational Myology, Department of Biomedical Sciences, University of Padova;Sorbonne Universités, UPMC Univ Paris 06 (CNRS, UMR 8256, INSERM ERL U1164), Institut Biologie Paris-Seine, Paris, France

关键词: rat;    Sternomastoid muscle;    muscle fiber types;    SDH;    myofibrillar ATPases;    regional distribution;   

DOI  :  10.4081/ejtm.2018.7302

学科分类：农业科学（综合）

来源: Pagepress

【 摘 要 】

The sternomastoid (SM) muscle in rodents is known to have a peculiar distribution of fiber types with a steep gradient from surface to deep region. We here further characterize this peculiar regional distribution by quantitative histochemical morphometrys. In Hematoxylin-Eosin (H-E) stained transverse cryosections harvested in the medial portion of the muscle we counted around 10.000 myofibers with a mean diameter of 51.3±12.6 (μm). Cryisections of the SM stained by SDH reaction clearly show two distinct regions, toward the deep surface of the muscle a 40% area that contains packed SDH-positive myofibers, while the remaining area of the SM toward the external surface presents a more checker-board appearance. On the other hand, in the deep region of SM type 1 (slow contracting) muscle fibers, caracterized by positive acidic ATPase pH 4.35 reaction, are only the 24.5% of the fibers in the deep area of SM muscles, being restricted to the deepest region. The 75.5% of the myofibers in the deep region are of the fast contracting types (either 48.4% 2A, SDH –positive fibers or 27.1% 2B, SDH-negative fibers, respectively). As expected the 2B muscle fibers, acidic ATPase pH 4.3-negative and SDH-negative, present the largest size, while Type 1 fibers, acidic ATPase pH 4.3-positive and SDH-positive, present the smallest size in rat SM muscle. Based on present and previous observations, comparison of change in absolute number and/or percentage of the fiber types in any experimental model of muscle atrophy/hypertrophy/plasticity/pathology /recovery in the rat SM, and possibly of all mammals, will ask for morphometry of the whole muscle cross-sections, muscle sampling by bioptic approches will provide only comparable data on the size of the different types of muscle fibers.

【 授权许可】

CC BY