BETHESDA, Md. (Dec. 17, 2012)It is well known that people with Down syndrome (DS) suffer from marked muscle weakness. Even the simple tasks of independent living, such as getting out of a chair or climbing a flight of stairs, can become major obstacles. This can reduce the quality of life for those with DS and lead to a loss of independence. Now, a new study sheds light on some of the suspected causes of muscle weakness.
Led by scientists from Syracuse University, a research team has investigated muscle weakness in a mouse model of DS. "If we understand the cause of this muscle weakness, we can begin to look at potential therapies for treating it," said Patrick M. Cowley, lead researcher.
The investigators analyzed the soleus musclea muscle in the lower legand looked into whether the weakness was due to a deficiency of the muscle itself, independent of its activation by the nervous system.
"Surprisingly, we found that the strength of the muscle itself was the same between the DS and control micesuggesting that factors in the nervous system may play a more dominant role in explaining muscle weakness in DS," said Cowley.
The article is entitled "Functional and Biochemical Characterization of the Soleus Muscle in Down Syndrome Mice: Insight into the Muscle Dysfunction Seen in the Human Condition," (http://bit.ly/TXsmby) It appears in the online edition of the American Journal of Physiology Regulatory, Integrative and Comparative Physiology published by the American Physiological Society (APS).
The researchers removed soleus muscles from 14 DS mice and 16 controls. They tested the muscles for strength, fatigue and recovery. They also assessed the distribution of fiber types in muscles from both groups.
Because there are three copies instead of two of chromosome 21 in persons with DS, the researchers looked at whether th
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American Physiological Society