In:
Medicine & Science in Sports & Exercise, Ovid Technologies (Wolters Kluwer Health), Vol. 56, No. 4 ( 2024-4), p. 612-622
Abstract:
Short periods of limb immobilization lower myofibrillar protein synthesis rates. Within skeletal muscle, the extracellular matrix of connective proteins is recognized as an important factor determining the capacity to transmit contractile force. Little is known regarding the impact of immobilization and subsequent recovery on muscle connective protein synthesis rates. This study examined the impact of 1 wk of leg immobilization and 2 wk of subsequent ambulant recovery on daily muscle connective protein synthesis rates. Methods Thirty healthy, young (24 ± 5 yr) men were subjected to 7 d of one-legged knee immobilization followed by 14 d of ambulant recovery. Deuterium oxide ingestion was applied over the entire period, and muscle biopsy samples were collected before immobilization, after immobilization, and after recovery to measure muscle connective protein synthesis rates and mRNA expression of key extracellular matrix proteins (collagen I, collagen III), glycoproteins (fibronectin, tenascin-C), and proteoglycans (fibromodulin, and decorin). A two-way repeated-measures (time–leg) ANOVA was used to compare changes in muscle connective protein synthesis rates during immobilization and recovery. Results During immobilization, muscle connective protein synthesis rates were lower in the immobilized (1.07 ± 0.30%·d −1 ) compared with the nonimmobilized (1.48 ± 0.44%·d −1 ; P 〈 0.01) leg. When compared with the immobilization period, connective protein synthesis rates in the immobilized leg increased during subsequent recovery (1.48 ± 0.64%·d −1 ; P 〈 0.01). After recovery, skeletal muscle collagen I, collagen III, fibronectin, fibromodulin, and decorin mRNA expression increased when compared with the postimmobilization time point (all P 〈 0.001). Conclusions One week of leg immobilization lowers muscle connective protein synthesis rates. Muscle connective protein synthesis rates increase during subsequent ambulant recovery, which is accompanied by increased mRNA expression of key extracellular matrix proteins.
Type of Medium:
Online Resource
ISSN:
1530-0315
,
0195-9131
DOI:
10.1249/MSS.0000000000003342
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2024
detail.hit.zdb_id:
2031167-9
SSG:
31
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