Effects of Acute Exercise on Remodeling of the Skeletal Muscle Extracellular Matrix Gene Expression

Aging is commonly accompanied by a progressive loss of skeletal muscle mass and function, or sarcopenia.

A vital structure that may change with advancing age is the muscle’s extracellular matrix (ECM). The ECM consists of a mesh of collagenous components as well as a mixture of further macromolecules, including various glycoproteins, proteoglycans, and elastin. Its functions include not only the mechanical support of the muscle fibers, nerves, and blood vessels but also the communication with other cells such as myoblasts, fibroblasts or inflammatory cells. ECM plays a significant role in controlling muscle growth, repair, and regeneration through its influence on satellite cells.

A study from Austria tested the potential of different exercises to counter these changes by stimulating the activity of genes associated with ECM remodelling.

Twenty-six healthy men (66.9 ± 3.9 years) were stratified to two of four groups, performing unilateral

• conventional resistance exercise,
• conventional resistance exercise followed by self-myofascial release/foam rolling (CEBR),
• eccentric-only exercise (ECC) or
• plyometric jumps (PLY).

The non-trained leg served as control. Six hours post-exercise, vastus lateralis muscle biopsy samples were analyzed for the expression of genes associated with ECM collagen synthesis (COL1A1), matrix metallopeptidases (collagen degradation; MMPs), and peptidase inhibitors (TIMP1).

Six hours after exercise, significant differences were found in the expressions of MMP3, MMP15 and TIMP1. The greatest responses in MMP3 and TIMP1 were observed after conventional resistance exercise, followed by foam rolling (CEBR). MMP15 reacting most strongly to eccentric-only exercise (ECC).

Further strong, albeit not statistically significant, upregulations of MMP9, COL1A1 and the MMP9:COL1A1 ratio following CEBR and plyometric training (PLY) suggest that these two exercise modalities trigger either earlier or more substantial remodeling of the network of intramuscular connective tissues than the other stimuli tested.

In conclusion, the study indicated the effectiveness of different exercise stimuli on the mRNA level of genes associated with skeletal muscle ECM remodeling in elderly men. The expression of ECM-related genes is exercise-specific, with CEBR and PLY triggering either earlier or stronger remodeling than other stimuli. Future studies need to verify whether such exercises may help counter age-associated muscle loss.