An Overview of Muscle Regeneration Following Acute Injury

Abstract

The focus of this research was to investigate the efects of acute blunt trauma, on the ultrastructural and protein content of skeletal muscles. A simple device for producing a humane and reproducible experimental model of blunt trauma to rat muscle was used. Ultrastructural events in the traumatized muscle were observed over 14 days. From 0 to 2 days after trauma there was a marked loss of muscle protein content, associated with an acute inflammatory response. From day 3 to 14 days, the muscle underwent regeneration with a rapid proliferation of sarcolemmal nuclei, activation of satellite cells, and the restoration of sarcomeres. By three days post trauma, muscle protein content decreased (35-47%) compared to muscle of control rats (p>0.05).

Effects on the ubiquitin proteasome system after closed soft-tissue trauma in rat skeletal muscle

“…The UPP activity measured 2 days after trauma was consistent with gene expression data for several proteasome subunits [38]. Further post-traumatic reactions we observed, such as the accumulation of endogenous ubiquitin and systemic effects, are novel details in a complex process of muscle regeneration after injury [34,46,47]. In contrast to pathological and physiological stress situations, muscle injury initiates a repair process that is characterized by a 3-4 week healing timeline with coordinated phases of degeneration, inflammation and regeneration.…”

“…Results revealed-in line with the present work-reduced ubiquitination activity after injury, but also proteasome activation. These controversial Studies of post-trauma ultrastructural events [33,34], changes in microcirculation [20,24,35], and metabolic effects of surgical trauma [36,37] are supplemented only by the work of Farges et al [38]. The results of this research supporting a lysosomal, UPP-independent protein breakdown by inflammatory infiltrated cells revealed a mechanism that was different from systemically induced muscle wasting.…”

Satellite cell activity in muscle regeneration after contusion in rats

“…2f). This time point reflects the initial phase of regeneration 34 . By Day 7, muscle regeneration was evident with the appearance of small‐calibre myotubes and myotubes with central nuclei, hallmarks of regenerating myofibres (Fig.…”

Switching to fast growth: the insulin-like growth factor (IGF) system in skeletal muscle of Atlantic salmon

“…Muscle is a complex tissue made up of several cell types that must be coordinately regulated during growth. The ECM (connective tissue) has been found to control the development and cellular metabolism of muscle fibres (Fisher and Rathgaber, 2006). The importance of the ECM in regulating muscle growth and differentiation has been highlighted.…”

“…For example expression of myogenin alone was not sufficient for the formation of skeletal muscle, with ECM being required to allow complete differentiation of cultured skeletal muscle cells (Osses and Brandan, 2002;Massague et al, 1986). Contained within the ECM is the basement membrane, which appears to play a role as a guide for newly forming myotubes (Fisher and Rathgaber, 2006). Further analysis of IGFBP-4 expression in fish species should elucidate its tissue localisation as well as growth inhibitory/promotion properties.…”