Cytoskeletal protein contents before and after hindlimb suspension in a fast and slow rat skeletal muscle

Abstract

Transversal cytoskeletal organization of muscle fibers is well described, although very few data are available concerning protein content. Measurements of desmin, alpha-actinin, and actin contents in soleus and extensor digitorum longus (EDL) rat skeletal muscles, taken with the results previously reported for several dystrophin-glycoprotein complex (DGC) components, indicate that the contents of most cytoskeletal proteins are higher in slow-type fibers than in fast ones. The effects of hypokinesia and unloading on the cytoskeleton were also investigated, using hindlimb suspension. First, this resulted in a decrease in contractile protein contents, only after 6 wk, in the soleus. Dystrophin and associated proteins were shown to be reduced for soleus at 3 wk, whereas only the dystrophin-associated proteins were found to increase after 6 wk. On the other hand, the contents of DGC components were increased for EDL for the two durations. Desmin and alpha-actinin levels were unchanged in the same conditions. Consequently, it can be concluded that the cytoskeletal protein expression levels could largely contribute to muscle fiber adaptation induced by modified functional demands.

Eccentric contraction-induced injury to type I, IIa, and IIa/IIx muscle fibers of elderly adults

“…Cross-bridge kinetics are altered with aging (Larsson et al 1997;Thompson and Brown 1999;Lowe et al 2001;Frontera et al 2000;Hook et al 2001;Krivickas et al 2001) but whether these changes are directly responsible for an age-related increase in damage is unknown. Alternatively, desmin, titin, myosin light chain 2, tropomyosin, and α-actinin covary (either in concentration or isoform expression) with fiber MHC isoform content (Prado et al 2005;Chopard et al 2001;Schiaffino and Reggiani 1996) and have all been implicated in contraction-induced muscle injury (Meyer et al 2010;Lieber et al 1996;Koh and Escobedo 2004;Zhang et al 2008;Lehti et al 2007;Belcastro 1993;Childers and McDonald 2004). Finally, an age-related increase in susceptibility to damage could be due to environmental factors.…”

Effects of Static Load on the Weight and Protein Content in the Leg Muscles of the Mouse: a Simulation of Prolonged Standing in the Workplace

“…Studies on mice 8) and white leghorns 21) showed that during the first few days of centrifugation, the centrifuged group lost weight and, thereafter, the weight of the centrifuged group got closer to that of the control group. These findings suggested that long term centrifugation would not be a severe stress.…”

“…Proteins were extracted from the frozen muscles according to the method described by Chopard et al 8) . Samples were pulverized in a small potter's mortar that had been cooled by liquid N 2 , and then homogenized in buffer containing 5 mM Tris, 10% Sodium Dodecylsulfate (SDS), 0.2 M 1,4-dithiothreitol, 1 mM Ethylenediaminetetraacetic acid (EDTA), and 2.5% protein inhibitor cocktail (Sigma, St. Louis, USA).…”

“…As it was reported that in hypogravity environment the cytoskeletal protein content of leg muscle changed 8) , protein content of leg muscle could be considered to change in a hypergravity environment. We expected that intermediate filaments which fortify the muscle ultrastructure would increase in muscle, since laboratory animals exposed to hypergravity needed more power to stand than with terrestrial gravity.…”

Subcellular proteomics of mice gastrocnemius and soleus muscles

“…In rodents, especially mice and rats, muscle fibers present a more uniform distribution among the different muscles, allowing the use of the entire muscles to study specific phenotypes. In this regard, the soleus and the white portion of gastrocnemius of mice are composed mainly of fast-and slow-twitch muscle fibers, respectively [5][6][7], and these two muscles have been used as typical models in proteomics. During the past few years, several studies have been performed using two-dimensional gel electrophoresis (2-DE) 1 combined with mass spectrometry (MS) to characterize skeletal muscle protein composition of typical slow-and fast-twitch skeletal muscles [8][9][10][11][12][13][14][15][16][17].…”