Analysis of changes in mRNA levels of myoblast‐ and fibroblast‐derived gene products in healing skeletal muscle using quantitative reverse transcription‐polymerase chain reaction

Abstract

Changes in expression of type I l l al-collagen and myosin I1 heavy chains were characterized in rabbit skeletal muscle following single stretch injury using quantitative reverse transcription-polymerase chain reaction. Collagen 111 expression was highly elevated in the injured leg compared with the control limb both at the myotendinous junction and in the distal muscle belly. While upregulation of collagen I11 expression at the myotendinous junction was maximal on day 1. collagen 111 expression in the distal muscle belly was unchanged on day 1 but highly elevated by day 3. Over the initial 7-day period, there was on average a 94% increase in collagen Ill expression at the myotendinous junction and a 41% increase in the distal muscle belly. On the other hand, there was little difference, in fact, slightly less expression of myosin I1 isoforms, in the injured leg compared with the control side. Immunohistochemical analysis of injured muscle showed significant collagen 111 deposition at the myotendinous junction beginning at day 3 post-injury and still evident by day 14. Focal deposits of type I and 111 collagen were first apparent in the distal muscle belly by day 3 and striking by day 7. Taken together, the data suggest the formation of connective tissue scar at the injury site and the absence of significant muscle regeneration following muscle stretch. Furthermore, microinjuries distant to the primary site of injury may result in more general muscle fibrosis and scarring. 0 3001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

Micro 3D Culture System using Hyaluronan-Collagen Capsule for Skeletal Muscle-Derived Stem Cells~!2009-07-29~!2010-02-03~!2010-04-28~!

“…Other growth factors and/or cytokines with higher molecular weights than VEGF may also become concentrated in the capsules. Reports that direct cell-cell interaction between fibroblasts induces expression of VEGF [24,25] also support the present results. However, encapsulated Sk-EECs showed copacetic proliferation and differentiation, thus further indicating that nutritional and other factors in the culture medium continuously affected Sk-EEC growth in the capsule, which suggests that low-weight molecules can pass through the HA-collagen capsule with relative ease, while larger molecules and/or vigorously expressed molecules accumulated.…”

“…The present Sk-EECs were isolated by the same methods as for Sk-34 cells [12][13][14][16][17][18], and they were not sorted (total cell fraction); thus, they included Sk-34 and other stem cells [13,14,16,17]. Skeletal muscle also includes fibroblasts in their connective networks [24,25], which may have contaminated the Sk-EECs and contributed to bFGF expression. For these reasons, concentrated VEGF and bFGF probably induced serial alignment of skeletal muscle derived myo-endothelial cells.…”

MR observations of long-term musculotendon remodeling following a hamstring strain injury

“…It has been hypothesized that scar tissue formation, along with weakness or atrophy of the previously injured muscle may be contributing factors to re-injury [8]. Indeed, prior animal models of injury have shown that muscle tissue may not be able to fully regenerate to pre-injury state, with connective scar tissue persisting at the site of injury indefinitely [18, 19]. Given that most hamstring strain injuries occur along the proximal musculotendon junction [20], where the muscle fibrils intersect with the tendon [17] (Fig.…”

Lesão muscular: fisiopatologia, diagnóstico, tratamento e apresentação clínica

“…Growth factors and cytokines are potent mitogenic activators for very many cells, including MPC cells during the regeneration of injured muscle cells (24) . Therefore, these are promising therapeutic options for assisting in recovering the skeletal musculature.…”