Cell proliferation in rat skeletal muscle during early stages of compensatory hypertrophy

1972 ◽  
Vol 11 (1) ◽  
pp. 268-273
Author(s):  
S. Schiaffino ◽  
S. Pierobon Bormioli ◽  
M. Aloisi
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Compensatory Hypertrophy ◽  
Rat Skeletal Muscle ◽  
Early Stages

scholarly journals COX-2 inhibitor reduces skeletal muscle hypertrophy in mice

2009 ◽  
Vol 296 (4) ◽  
pp. R1132-R1139 ◽  
Author(s):  
Margaret L Novak ◽  
William Billich ◽  
Sierra M. Smith ◽  
Kunal B. Sukhija ◽  
Thomas J. McLoughlin ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Muscle Hypertrophy ◽  
Muscle Growth ◽  
Muscular Activity ◽  
Compensatory Hypertrophy ◽  
Cell Nuclei ◽  
Skeletal Muscle Hypertrophy ◽  
Cox 2 ◽  
Macrophage Accumulation

Anti-inflammatory strategies are often used to reduce muscle pain and soreness that can result from high-intensity muscular activity. However, studies indicate that components of the acute inflammatory response may be required for muscle repair and growth. The hypothesis of this study was that cyclooxygenase (COX)-2 activity is required for compensatory hypertrophy of skeletal muscle. We used the synergist ablation model of skeletal muscle hypertrophy, along with the specific COX-2 inhibitor NS-398, to investigate the role of COX-2 in overload-induced muscle growth in mice. COX-2 was expressed in plantaris muscles during compensatory hypertrophy and was localized mainly in or near muscle cell nuclei. Treatment with NS-398 blunted the increases in mass and protein content in overloaded muscles compared with vehicle-treated controls. Additionally, the COX-2 inhibitor decreased activity of the urokinase type plasminogen activator, macrophage accumulation, and cell proliferation, all of which are required for hypertrophy after synergist ablation. Expression of insulin-like growth factor-1 and phosphorylation of Akt, mammalian target of rapamycin, and p70S6K were increased following synergist ablation, but were not affected by NS-398. Additionally, expression of atrogin-1 was reduced during hypertrophy, but was also not affected by NS-398. These results demonstrate that COX-2 activity is required for skeletal muscle hypertrophy, possibly through facilitation of extracellular protease activity, macrophage accumulation, and cell proliferation.

scholarly journals Regulation of myosin heavy-chain gene expression during skeletal-muscle hypertrophy

1989 ◽  
Vol 257 (3) ◽  
pp. 691-698 ◽  
Author(s):  
M Periasamy ◽  
P Gregory ◽  
B J Martin ◽  
W S Stirewalt
Keyword(s):  
Skeletal Muscle ◽  
Muscle Hypertrophy ◽  
Compensatory Hypertrophy ◽  
Chain Gene ◽  
Mrna Levels ◽  
Muscle Adaptation ◽  
Myosin Heavy Chain Gene ◽  
Rat Skeletal Muscle ◽  
Skeletal Muscle Hypertrophy ◽  
Myosin Isoenzymes

Changes in the myosin phenotype of differentiated muscle are a prominent feature of the adaptation of the tissue to a variety of physiological stimuli. In the present study the molecular basis of changes in the proportion of myosin isoenzymes in rat skeletal muscle which occur during compensatory hypertrophy caused by the combined removal of synergist muscles and spontaneous running exercise was investigated. The relative amounts of sarcomeric myosin heavy (MHC)- and light (MLC)-chain mRNAs in the plantaris (fast) and soleus (slow) muscles from rats was assessed with cDNA probes specific for different MHC and MLC genes. Changes in the proportion of specific MHC mRNA levels were in the same direction as, and of similar magnitude to, changes in the proportion of myosin isoenzymes encoded for by the mRNAs. No significant changes in the proportion of MLC proteins or mRNA were detected. However, high levels of MLC3 mRNA were measured in both normal and hypertrophied soleus muscles which contained only trace amounts of MLC3 protein. Small amounts of embryonic and neonatal MHC mRNAs were induced in both muscles during hypertrophy. We conclude that the change in the pattern of myosin isoenzymes during skeletal-muscle adaptation to work overload is a consequence of changes in specific MHC mRNA levels.

Sign in / Sign up

Export Citation Format

Share Document