THE ESSENTIAL
- MIT researchers have discovered that the growth of motor neurons is stimulated by physical activity.
- They grow up to 4 times further.
- This development is linked to chemical and mechanical signals coming from the muscles.
Exercising regularly is not only good for your heart and breathing, it is also beneficial for your neurons. MIT engineers noticed that contracting muscles during physical exercise leads to the release of biochemical signals called myokines. And these promote the development of neurons.
This discovery was the subject of an article in the journal Advanced Healthcare Materials.
Physical activity: neurons go four times further
Wishing to determine whether physical exercise had a direct effect on neuron growth, the researchers grew mouse muscle cells into long fibers. At the same time, this created “muscle” was genetically modified to contract in response to light.
“With this modification, the team was able to flash a light repeatedly, causing the muscle to contract in response, in a way that mimicked exercise.”specifies the press release. The team then recovered the fluid in which these muscle cells were located, and which contained the myokines secreted during contractions. This solution was transferred to a dish containing motor neurons. That is to say the nerve cells present in the spinal cord which control the muscles involved in voluntary movements.
The team observed that these neurons, exposed to myokines, grew four times faster than neurons that had not received the biochemical solution. “They grow much further and faster, and the effect is quite immediate,” says Ritu Raman of MIT.
Neurons that “exercise” grow faster
The scientists then did a genetic analysis, extracting RNA from the neurons to see if the myokines induced a change in the expression of certain neuronal genes. “We found that many genes upregulated in exercise-stimulated neurons were not only related to neuron growth, but also to their maturation, their ability to communicate with muscles and other nerves , and at the maturity of the axons, explains the expert. Exercise appears to have an impact not only on the growth of neurons, but also on their maturity and proper functioning.”
The researchers wondered whether neuron growth could also be linked to the mechanical forces of exercise. To answer their question, they grew motor neurons on a gel mat into which they embedded tiny magnets. They then used an external magnet to move the mat – and the neurons – back and forth. They thus have “gets exercise” to neurons for 30 minutes per day. The results revealed that mechanical activity stimulated neuron growth just as much as that of neurons in contact with myokine, and that they grew significantly further than neurons that had not received any form of exercise.
“This is a good sign, because it tells us that the biochemical and physical effects of exercise are equally important”adds Ritu Raman.
Scientists say their work, showing that muscle exercise can promote nerve growth at the cellular level, could help develop new therapies to repair damaged nerves and neurons.
