There's no doubt that exercise does a body good, including strengthening and toning our muscles. But how exactly does exercise make this happen?
As we run and lift and stretch, our muscles experience chemical signals from surrounding cells, as well as mechanical forces from jostling against tissues. Some physiologists wonder: Is it the body's natural chemical stimulants or the physical forces of repeated motion -; or some mix of the two -; that ultimately drive our muscles to grow? The answer could be the key to identifying therapies to help people recover from muscle injuries and neurodegenerative disorders.
To activate the gel's mechanical function, the researchers used an external magnet underneath the mat to move the embedded particles back and forth, wobbling the gel in turn like a vibrating mat. They controlled the frequency of the wobbling to mimic the forces that muscles would experience during actual exercise.
We hope to use this new platform to see whether mechanical stimulation could help guide muscle regrowth after injury or lessen the effects of aging. Mechanical forces play a really important role in our bodies and lived environment. And now we have a tool to study that." She and her colleagues have published their results in the journal Device.
Related StoriesThe team looked for a way to expose muscle cells to regular and repeated mechanical forces, that at the same time would not physically damage them in the process. They ultimately landed on magnets a safe and nondestructive way to generate mechanical forces. Finally, the researchers placed an external magnet on a track beneath the gel mat and programmed the magnet to move back and forth. The embedded magnets moved in response, wobbling the gel and generating forces that are similar to what cells would experience during actual exercise. The team mechanically "exercised" the cells for 30 minutes a day, for 10 days. As a control, they grew cells on the same mat, but left them to grow without exercising them.
The muscle cells that the team used in this study were genetically engineered to contract in response to blue light. Typically, muscle cells in the body contract in response to a nerve's electrical pulse. Electrically stimulating muscle cells in the lab, however, could potentially damage them, so the team chose to genetically manipulate the cells to contract in response to a noninvasive stimulus -; in this case, blue light.