The distribution of myosin heavy (MyHC) and myosin light chain (MyLC) isoform pattern in horse, rat and human skeletal muscle was investigated to establish relations between them and the role of myosin isoform pattern...The distribution of myosin heavy (MyHC) and myosin light chain (MyLC) isoform pattern in horse, rat and human skeletal muscle was investigated to establish relations between them and the role of myosin isoform patterns in mammalian muscle with different twitch characteristics was studied. These two isoforms were separated in a SDS-PAGE gel system, stained using the coomassie and silver staining procedures, and the results were analyzed using a G:BOX system. The relative content of MyHC I isoform in muscle was 2.6 times higher than in human compared to horse muscle (p < 0.001), and 6.3 times higher than in rat muscle (p < 0.001). The relative content of MyHC IIx/d isoform in horse muscle is 2.7 times, and in rat muscle 2.2 times higher in comparison with human muscle (p < 0.001). The role of the MyLC isoform distribution in mammalian skeletal muscle seems to depend on the oxidative capacity of muscles.展开更多
Viscoelastic properties of skeletal muscle are associated with a complex network of cytoskeletal proteins where titin and nebulin play a substantial role. The need for evaluation of muscle viscoelastic properties is w...Viscoelastic properties of skeletal muscle are associated with a complex network of cytoskeletal proteins where titin and nebulin play a substantial role. The need for evaluation of muscle viscoelastic properties is widely accepted in clinical use to evaluate the effect of treatment or progression of muscle pathology (atrophy). We tested the hypothesis that the viscoelastic properties (elasticity, tone and stiffness) change in atrophied muscles with concomitant changes in cytoskeletal proteins (titin, nebulin) and contractile protein (myosin heavy chain) proportion. Sixteen 24- week-old male rats of the Wistar strain were randomly allocated to two groups: dexamethasone group treated each day for 10 consecutive days with dexamethasone in order to induce atrophy and control group. Skeletal muscle viscoelastic properties (elasticity, tone and stiffness) were determined using a myotonometer. Titin, nebulin and myosin heavy chain content were quantified using SDS-PAGE electrophoresis. We found that glucocorticoid-induced muscle atrophy is accompanied by reduced elasticity and increased tone and stiffness, with concomitant changes in titin, nebulin and myosin heavy chain con- tent. The elasticity decreased by 10.9% (P P < 0.05), and stiffness was significantly lower in dexamethasone group (627.3 N/m vs 758.6 N/m);(P < 0.05). Compared with the control group, the content of titin, nebulin and myosin heavy chain in atrophied muscle was 76.4%, 70.6% and 82.3%, respectively. Our results may lead to a better understanding of the mechanism of muscle atrophy and provide better guidance for rehabilitation practices and help to find rational therapeutic intervention in the future.展开更多
基金supported by the funds of the Ministry of Education and Research of the Republic of Estonia,research project number TKKSB1787.
文摘The distribution of myosin heavy (MyHC) and myosin light chain (MyLC) isoform pattern in horse, rat and human skeletal muscle was investigated to establish relations between them and the role of myosin isoform patterns in mammalian muscle with different twitch characteristics was studied. These two isoforms were separated in a SDS-PAGE gel system, stained using the coomassie and silver staining procedures, and the results were analyzed using a G:BOX system. The relative content of MyHC I isoform in muscle was 2.6 times higher than in human compared to horse muscle (p < 0.001), and 6.3 times higher than in rat muscle (p < 0.001). The relative content of MyHC IIx/d isoform in horse muscle is 2.7 times, and in rat muscle 2.2 times higher in comparison with human muscle (p < 0.001). The role of the MyLC isoform distribution in mammalian skeletal muscle seems to depend on the oxidative capacity of muscles.
文摘Viscoelastic properties of skeletal muscle are associated with a complex network of cytoskeletal proteins where titin and nebulin play a substantial role. The need for evaluation of muscle viscoelastic properties is widely accepted in clinical use to evaluate the effect of treatment or progression of muscle pathology (atrophy). We tested the hypothesis that the viscoelastic properties (elasticity, tone and stiffness) change in atrophied muscles with concomitant changes in cytoskeletal proteins (titin, nebulin) and contractile protein (myosin heavy chain) proportion. Sixteen 24- week-old male rats of the Wistar strain were randomly allocated to two groups: dexamethasone group treated each day for 10 consecutive days with dexamethasone in order to induce atrophy and control group. Skeletal muscle viscoelastic properties (elasticity, tone and stiffness) were determined using a myotonometer. Titin, nebulin and myosin heavy chain content were quantified using SDS-PAGE electrophoresis. We found that glucocorticoid-induced muscle atrophy is accompanied by reduced elasticity and increased tone and stiffness, with concomitant changes in titin, nebulin and myosin heavy chain con- tent. The elasticity decreased by 10.9% (P P < 0.05), and stiffness was significantly lower in dexamethasone group (627.3 N/m vs 758.6 N/m);(P < 0.05). Compared with the control group, the content of titin, nebulin and myosin heavy chain in atrophied muscle was 76.4%, 70.6% and 82.3%, respectively. Our results may lead to a better understanding of the mechanism of muscle atrophy and provide better guidance for rehabilitation practices and help to find rational therapeutic intervention in the future.
