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Ultrastructural features of the myotendinous junction of the sternomastoid muscle in Wistar rats: From newborn to aging
Author(s) -
Ciena Adriano Polican,
De Almeida Sonia Regina Yokomizo,
De Sousa Bolina Cristina,
De Sousa BolinaMatos Regina,
Grassi Rici Rose Eli,
Da Silva Marcelo Cavenaghi Pereira,
Miglino Maria Angélica,
Watanabe IiSei
Publication year - 2012
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.22063
Subject(s) - sarcolemma , anatomy , ultrastructure , sarcomere , extracellular matrix , gap junction , chemistry , biology , myocyte , skeletal muscle , biophysics , microbiology and biotechnology , intracellular
The myotendinous junction (MTJ) is a major area for transmitting force from the skeletal muscle system and acts in joint position and stabilization. This study aimed to use transmission electron microscopy to describe the ultrastructural features of the MTJ of the sternomastoid muscle in Wistar rats from newborn to formation during adulthood and possible changes with aging. Ultrastructural features of the MTJ from the newborn group revealed pattern during development with interactions between muscle cells and extracellular matrix elements with thin folds in the sarcolemma and high cellular activity evidenced through numerous oval mitochondria groupings. The adult group had classical morphological features of the MTJ, with folds in the sarcolemma forming long projections called “finger‐like processes” and sarcoplasmic invaginations. Sarcomeres were aligned in series, showing mitochondria near the Z line in groupings between collagen fiber bundles. The old group had altered “finger‐like processes,” thickened in both levels of sarcoplasmic invaginations and in central connections with the lateral junctions. We conclude that the MTJ undergoes intense activity from newborn to its formation during adulthood. With increasing age, changes to the MTJ were observed in the shapes of the invaginations and “finger‐like processes” due to hypoactivity, potentially compromising force transmission and joint stability. Microsc. Res. Tech. 75:1292–1296, 2012. © 2012 Wiley Periodicals, Inc.