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Age-related changes in rat intrinsic laryngeal muscles: analysis of muscle fibers, muscle fiber proteins, and subneural apparatuses.
- Source :
-
European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery [Eur Arch Otorhinolaryngol] 2013 Mar; Vol. 270 (3), pp. 975-84. Date of Electronic Publication: 2012 Oct 26. - Publication Year :
- 2013
-
Abstract
- We compared age-related changes in the intrinsic laryngeal muscles of aged and young adult rats by determining the number and diameter of muscle fibers, contractile muscle protein (myosin heavy chain isoforms, MHC) composition, and the morphology of the subneural apparatuses. In aged rats, both the numbers and the diameters of muscle fibers decreased in the cricothyroid (CT) muscle. The number of fibers, but not diameter, decreased in the thyroarytenoid (TA) muscle. In the posterior cricoarytenoid (PCA) muscle, neither the number nor the diameter of fibers changed significantly. Aging was associated with a decrease in type IIB and an increase in type IIA MHC isoform levels in CT muscle, but no such changes were observed in the TA or PCA muscles. Morphological examination of primary synaptic clefts of the subneural apparatus revealed that aging resulted in decreased labyrinthine and increased depression types in only the CT muscle. In the aged group, morphologically immature subneural apparatuses were found infrequently in the CT muscle, indicating continued tissue remodeling. We suggest, therefore, that age-related changes in the intrinsic laryngeal muscles primarily involve the CT muscle, whereas the structures of the TA and PCA muscles may better resist aging processes and therefore are less vulnerable to functional impairment. This may reflect differences in their roles; the CT muscle controls the tone of the vocal folds, while the TA and PCA muscles play an essential role in vital activities such as respiration and swallowing.
- Subjects :
- Aging metabolism
Animals
Cell Count
Cell Size
Female
Laryngeal Muscles metabolism
Microscopy, Electron, Scanning
Muscle Fibers, Skeletal metabolism
Muscle Fibers, Skeletal ultrastructure
Rats
Rats, Wistar
Aging pathology
Laryngeal Muscles cytology
Muscle Fibers, Skeletal pathology
Myosin Heavy Chains metabolism
Neuromuscular Junction ultrastructure
Subjects
Details
- Language :
- English
- ISSN :
- 1434-4726
- Volume :
- 270
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery
- Publication Type :
- Academic Journal
- Accession number :
- 23100084
- Full Text :
- https://doi.org/10.1007/s00405-012-2231-0