scholarly journals Synaptic activity and connective tissue remodeling in denervated frog muscle.

1994 ◽  
Vol 127 (5) ◽  
pp. 1435-1445 ◽  
Author(s):  
E A Connor ◽  
K Qin ◽  
H Yankelev ◽  
D DeStefano
Keyword(s):  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Connective Tissue ◽  
Muscle Activity ◽  
Tissue Remodeling ◽  
Interstitial Cells ◽  
Frog Muscle ◽  
Connective Tissue Remodeling ◽  
Denervated Frog Muscle

Denervation of skeletal muscle results in dramatic remodeling of the cellular and molecular composition of the muscle connective tissue. This remodeling is concentrated in muscle near neuromuscular junctions and involves the accumulation of interstitial cells and several extracellular matrix molecules. Given the role of extracellular matrix in neurite outgrowth and synaptogenesis, we predict that this remodeling of the junctional connective tissue directly influences the regeneration of the neuromuscular junction. As one step toward understanding the role of this denervation-induced remodeling in synapse formation, we have begun to look for the signals that are involved in initiating the junctional accumulations of interstitial cells and matrix molecules. Here, the role of muscle inactivity as a signal was examined. The distributions of interstitial cells, fibronectin, and tenascin were determined in muscles inactivated by presynaptic blockade of muscle activity with tetrodotoxin. We found that blockade of muscle activity for up to 4 wk produced neither the junctional accumulation of interstitial cells nor the junctional concentrations of tenascin and fibronectin normally present in denervated frog muscle. In contrast, the muscle inactivity induced the extrajunctional appearance of two synapse-specific molecules, the acetylcholine receptor and a muscle fiber antigen, mAb 3B6. These results demonstrate that the remodeling of the junctional connective tissue in response to nerve injury is a unique response of muscle to denervation in that it is initiated by a mechanism that is independent of muscle activity. Thus connective tissue remodeling in denervated skeletal muscle may be induced by signals released from or associated with the nerve other than the evoked release of neurotransmitter.

Role of Extracellular Matrix in Adaptation of Tendon and Skeletal Muscle to Mechanical Loading

2004 ◽  
Vol 84 (2) ◽  
pp. 649-698 ◽  
Author(s):  
MICHAEL KJÆR
Keyword(s):  
Physical Activity ◽  
Mechanical Properties ◽  
Skeletal Muscle ◽  
Extracellular Matrix ◽  
Connective Tissue ◽  
Mechanical Loading ◽  
Collagen Synthesis ◽  
Cross Linking ◽  
Collagen Turnover

Kjær, Michael. Role of Extracellular Matrix in Adaptation of Tendon and Skeletal Muscle to Mechanical Loading. Physiol Rev 84: 649–698, 2004; 10.1152/physrev.00031.2003.—The extracellular matrix (ECM), and especially the connective tissue with its collagen, links tissues of the body together and plays an important role in the force transmission and tissue structure maintenance especially in tendons, ligaments, bone, and muscle. The ECM turnover is influenced by physical activity, and both collagen synthesis and degrading metalloprotease enzymes increase with mechanical loading. Both transcription and posttranslational modifications, as well as local and systemic release of growth factors, are enhanced following exercise. For tendons, metabolic activity, circulatory responses, and collagen turnover are demonstrated to be more pronounced in humans than hitherto thought. Conversely, inactivity markedly decreases collagen turnover in both tendon and muscle. Chronic loading in the form of physical training leads both to increased collagen turnover as well as, dependent on the type of collagen in question, some degree of net collagen synthesis. These changes will modify the mechanical properties and the viscoelastic characteristics of the tissue, decrease its stress, and likely make it more load resistant. Cross-linking in connective tissue involves an intimate, enzymatical interplay between collagen synthesis and ECM proteoglycan components during growth and maturation and influences the collagen-derived functional properties of the tissue. With aging, glycation contributes to additional cross-linking which modifies tissue stiffness. Physiological signaling pathways from mechanical loading to changes in ECM most likely involve feedback signaling that results in rapid alterations in the mechanical properties of the ECM. In developing skeletal muscle, an important interplay between muscle cells and the ECM is present, and some evidence from adult human muscle suggests common signaling pathways to stimulate contractile and ECM components. Unaccostumed overloading responses suggest an important role of ECM in the adaptation of myofibrillar structures in adult muscle. Development of overuse injury in tendons involve morphological and biochemical changes including altered collagen typing and fibril size, hypervascularization zones, accumulation of nociceptive substances, and impaired collagen degradation activity. Counteracting these phenomena requires adjusted loading rather than absence of loading in the form of immobilization. Full understanding of these physiological processes will provide the physiological basis for understanding of tissue overloading and injury seen in both tendons and muscle with repetitive work and leisure time physical activity.

Effect of photobiomodulation on connective tissue remodeling and regeneration of skeletal muscle in elderly rats

2017 ◽  
Vol 33 (3) ◽  
pp. 513-521 ◽  
Author(s):  
Adriana de Brito ◽  
Agnelo Neves Alves ◽  
Beatriz Guimaraes Ribeiro ◽  
Daniel Victor D. Emilio Barbosa ◽  
Erick Moreno Ramos Magalhaes ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Connective Tissue ◽  
Tissue Remodeling ◽  
Connective Tissue Remodeling

scholarly journals Regulation of connective tissue remodeling in the early phase of denervation in a rat skeletal muscle

2013 ◽  
Vol 34 (5) ◽  
pp. 251-258 ◽  
Author(s):  
Junya OZAWA ◽  
Tomoyuki KUROSE ◽  
Seiichi KAWAMATA ◽  
Akinori KANEGUCHI ◽  
Hideki MORIYAMA ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Connective Tissue ◽  
Early Phase ◽  
Tissue Remodeling ◽  
Rat Skeletal Muscle ◽  
Connective Tissue Remodeling

scholarly journals Fibroblast Matrix Gene Expression and Connective Tissue Remodeling: Role of Endothelin-1

2001 ◽  
Vol 116 (3) ◽  
pp. 417-425 ◽  
Author(s):  
Xu Shi-wen ◽  
Christopher P. Denton ◽  
Alan M. Holmes ◽  
Carol M. Black ◽  
David J. Abraham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Connective Tissue ◽  
Tissue Remodeling ◽  
Endothelin 1 ◽  
Matrix Gene ◽  
Connective Tissue Remodeling

Markers of connective tissue remodeling in genital prolapse

GYNECOLOGY ◽  
2016 ◽  
Vol 18 (3) ◽  
Author(s):  
M.L Khanzadyan ◽  
V.E. Radzinskiy ◽  
T.A. Demura ◽  
A.V. Donnikov
Keyword(s):  
Connective Tissue ◽  
Tissue Remodeling ◽  
Genital Prolapse ◽  
Connective Tissue Remodeling

Decompression to altitude: assumptions, experimental evidence, and future directions

2009 ◽  
Vol 106 (2) ◽  
pp. 678-690 ◽  
Author(s):  
Philip P. Foster ◽  
Bruce D. Butler
Keyword(s):  
Skeletal Muscle ◽  
Experimental Evidence ◽  
Muscle Activity ◽  
Weight Bearing ◽  
Bubble Formation ◽  
Microgravity Environment ◽  
Physiological Variables ◽  
Orbital Space ◽  
Human Exploration

Although differences exist, hypobaric and hyperbaric exposures share common physiological, biochemical, and clinical features, and their comparison may provide further insight into the mechanisms of decompression stress. Although altitude decompression illness (DCI) has been experienced by high-altitude Air Force pilots and is common in ground-based experiments simulating decompression profiles of extravehicular activities (EVAs) or astronauts' space walks, no case has been reported during actual EVAs in the non-weight-bearing microgravity environment of orbital space missions. We are uncertain whether gravity influences decompression outcomes via nitrogen tissue washout or via alterations related to skeletal muscle activity. However, robust experimental evidence demonstrated the role of skeletal muscle exercise, activities, and/or movement in bubble formation and DCI occurrence. Dualism of effects of exercise, positive or negative, on bubble formation and DCI is a striking feature in hypobaric exposure. Therefore, the discussion and the structure of this review are centered on those highlighted unresolved topics about the relationship between muscle activity, decompression, and microgravity. This article also provides, in the context of altitude decompression, an overview of the role of denitrogenation, metabolic gases, gas micronuclei, stabilization of bubbles, biochemical pathways activated by bubbles, nitric oxide, oxygen, anthropometric or physiological variables, Doppler-detectable bubbles, and potential arterialization of bubbles. These findings and uncertainties will produce further physiological challenges to solve in order to line up for the programmed human return to the Moon, the preparation for human exploration of Mars, and the EVAs implementation in a non-zero gravity environment.

scholarly journals Morphological features and the functional state of connective tissue of the uterine rudiments in reproductive age patients with Mayer–Rokitansky–Küster–Hauser syndrome

2020 ◽  
Vol 9 (4) ◽  
pp. 24-30
Author(s):  
A.V. Asaturova ◽  
◽  
N.M. Faizullina ◽  
M.V. Bobkova ◽  
A.S. Arakelyan ◽  
...  
Keyword(s):  
Connective Tissue ◽  
Collagen Type ◽  
Tissue Remodeling ◽  
Collagen Type I ◽  
Morphological Features ◽  
Control Group ◽  
Type I ◽  
Variable Degree ◽  
Collagen Iii ◽  
Connective Tissue Remodeling

Introduction. Female patients with Mayer–Rokitansky–Küster–Hauser syndrome (MRKH) have high stigma scores; the condition severely affects the reproductive system. The study aimed at specification of morphological features and assessment of the maturity of connective tissues of the uterine rudiments in MRKH. Patients and methods. The study included 42 patients with vaginal and uterine aplasia having functioning uterine rudiments and 47 patients of the control group without genital malformations. Age of the patients was 20-24 years in 67.2% of the cases, and 31.2% of the patients were aged ≤ 19, inclusive. Immunohistochemi-cal assay was applied to determine expression levels of collagen I, collagen III, ММР2, ММР9, TIMP1, fibronectin and laminin proteins within the functioning uterine rudiments in comparison with levels of the same proteins in normally developed uterine tissues. Results. Decreased expression of collagen type I and elevated levels of MMP2 and MMP9 proteins in uterine tissues were observed for the group of patients with MRKH. Conclusions. 1) Uterine rudiments in patients with MRKH show variable degree of morphological similarity with the normally developed uterus; 2) The functioning uterine rudiments are subject to the same pathological processes as the normally developed uterus (myoma, endometriosis). 3) The functioning uterine rudiments in patients with MRKH show altered patterns of connective tissue remodeling, with decreased expression of collagen type I and increased expression of matrix metalloproteinases MMP2 and MMP9. Keywords: Müllerian aplasia, uterine rudiments, metalloproteinases, connective tissue remodeling, ММР2, ММР9

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