Regulation of extracellular matrix elements and sarcomerogenesis in response to different periods of passive stretching in the soleus muscle of rats

Abstract

Stretching is a common method used to prevent muscle shortening and improve limited mobility. However, the effect of different time periods on stretching-induced adaptation of the extracellular matrix and its regulatory elements have yet to be investigated. We aimed to evaluate the expression of fibrillar collagens, sarcomerogenesis, metalloproteinase (MMP) activity and gene expression of the extracellular matrix (ECM) regulators in the soleus (SOL) muscle of rats submitted to different stretching periods. The soleus muscles were submitted to 10 sets of passive stretching over 10 (St 10d) or 15 days (St 15d) (1 min per set, with 30 seconds’ rest between sets). Sarcomerogenesis, muscle cross-sectional area (CSA), and MMP activity and mRNA levels in collagen (type I, III and IV), connective tissue growth factor (CTGF), growth factor-beta (TGF-β), and lysyl oxidase (LOX) were analyzed. Passive stretching over both time periods mitigated COL-I deposition in the SOL muscle of rats. Paradoxically, 10 days of passive stretching induced COL-I and COL-III synthesis, with concomitant upregulation of TGF-β1 and CTGF at a transcriptional level. These responses may be associated with lower LOX mRNA levels in SOL muscles submitted to 10 passive stretching sessions. Moreover, sarcomerogenesis was observed after 15 days of stretching, suggesting that stretching-induced muscle adaptations are time-dependent responses.

Muscle unloading: A comparison between spaceflight and ground‐based models

“…ECM in the intramuscular connective tissues maintains tissue integrity and regulates passive mechanical properties of the skeletal muscle . Contractile activity induces collagen synthesis, which helps in skeletal muscle remodelling in response to functional demand .…”

“…ECM in the intramuscular connective tissues maintains tissue integrity and regulates passive mechanical properties of the skeletal muscle. 141 Contractile activity induces collagen synthesis, which helps in skeletal muscle remodelling in response to functional demand. 142 On the contrary, mechanical unloading of skeletal muscle results in reduced synthesis of muscle collagen at the post-translational levels.…”

Tendon Remodeling in Response to Resistance Training, Anabolic Androgenic Steroids and Aging

“…Skeletal muscle seems to be more sensitive than tendons in response to mechanical loading [90], which is supported by studies demonstrating elevated MMP expression in the muscle [93,114,115,116,117]. On the other hand, MMP expression seems to be differently regulated by mechanical loading in distinct regions of tendon (proximal and distal) [16], while, MMPs response might also be dependent on type and frequency of stimuli [118,119,120,121]. In this sense, further research is needed to a better understanding of mechanical loading effects on MMP expression in the tendons.…”

Recursos Do Meio Hídrico Aplicados Pelo Fisioterapeuta Em Prematuros Internados Em Unidade De Terapia Intensiva Neonatal: Revisão Integrativa De Literatura

“…Contudo, existe uma carência de modelos topográficos e histológicos que expliquem as interações entre o alongamento e as repercussões funcionais que ocorrem nos tecidos adjacentes, tais como tendões, nervos, ligamentos e fáscia (77). A comparação dos resultados da terapia com exercícios de alongamento em artigos clínicos apresenta limitações devido à falta de padronização, decorrente de protocolos diferentes que variam quanto à intensidade, à duração, à frequência dos movimentos e ao tempo que deveria ser despendido com o alongamento terapêutico, a fim de provocar os efeitos fisiológicos desejados (78,79).…”