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Assistant professor researches muscle atrophy |
| By
Deanna Woolf |
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Sep 20, 2005 |
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They are tiny, even for mice. The little puffs of black fur roll around in wood chips, sip water and nibble on food in the laboratory. Weighing in at around 15 grams, these rodents are dwarfed by their normal-sized counterparts that usually weigh between 25 and 30 grams. But these tiny mice are special, altered so that a protein atrophies their muscles. And they could hold the key for helping humans who experience muscle loss from injury, bed rest or space travel.
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| Dr. Thomas McLoughlin |
It's all part of a research project by Dr. Thomas McLoughlin, assistant professor of exercise physiology, to look at the protein FoxO1. "The protein appears to have a role in catabolism of muscles," he explained. "I'm trying to identify which genes get turned on and off by the protein." It's the changes in these genes that eventually lead to atrophy, or shrinking of the muscle's size and mass.
While researchers are still investigating how atrophy occurs on the molecular level, the physical process is well-understood. McLoughlin said that once a muscle is unloaded — weight taken off or function taken away — "it shrinks up." This can occur due to prolonged bed rest or injuries that require crutches or casts for treatment. When he worked as an athletic trainer, McLoughlin saw children's muscles atrophy from as little as two weeks wearing a cast. "It's really amazing," he said.
Even people at the peak of physical fitness can experience muscle atrophy. "You never really see astronauts coming off the ships," McLoughlin said. "Spending a few months in space, they lose muscle mass and some cardiovascular function. They're weak from the effects of microgravity when they return. They sometimes have to be carried off the ship." He said that with such strong atrophy in a relatively short amount of time, "it has implications when we talk about going to places as far away as Mars."
But that might be easier thanks to the mice, which were imported from and engineered in Japan to express FoxO1. Once at UT, the mice were bred and tested to verify that they contained the protein. "DNA from the mice is screened to determine the presence of the gene," McLoughlin said. "If the mice contain the gene, we study muscles from the mice to determine the role of the gene in the control of muscle atrophy."
McLoughlin's work has implications for more than kinesiology and exercise science. "For cancer regulation, atrophy would be a good thing," he said. "We would want to shut down the growth of the cells." The research also could help decrease the effects of aging. "We can avoid the cycle of becoming older and more frail, then being injured, recovering, and then getting older and more frail again."
In order to prevent muscle atrophy, McLoughlin advised people, "especially the elderly," to stay active and engage in strength training. He also said if a person is about to undergo surgery on places like the anterior cruciate ligament, he or she should expect some major training before the operation. "Doctors and therapists like to have you get the muscles as strong and as large as possible to minimize muscle loss during recovery," he said.
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