There’s no doubt that exercise does the body good – building muscles and strengthening our bones, blood vessels and immune systems – but MIT engineers have discovered that it also has health benefits. individual neurons.
They observed that when muscles contract during exercise, they release a soup of biochemical signals called myokines. In the presence of these muscle-generated signals, neurons grew four times further than neurons not exposed to myokines.
These experiments at the cellular level suggest that exercise can have a significant biochemical effect on nerve growth. Surprisingly, researchers also found that neurons respond not only to the biochemical signals of exercise, but also to its physical impacts.
While previous studies have indicated a potential biochemical link between muscle activity and nerve growth, this is the first to show that the physical effects may be just as important. The findings shed light on the connection between muscles and nerves during exercise and could shed light on exercise. -therapies related to nerve repair.
“Now that we know this muscle-nerve crosstalk exists, it can be useful for treating things like nerve damage, where the communication between the nerve and the muscle is cut off.” said Ritu Ramanassistant professor of mechanical engineering at MIT and lead author of the study. “Perhaps if we stimulate the muscle, we could encourage healing of the nerve and restore mobility to those who have lost it due to trauma or neurodegenerative disease.”
“Exercise as medicine”
In 2023, Raman and colleagues reported that they could restore mobility in mice that had suffered traumatic muscle injury, by first implanting muscle tissue at the injury site and then exercising the new tissue by stimulating it repeatedly with light. Over time, they found that the exercised graft helped the mice regain motor function, reaching activity levels comparable to healthy mice.
When the researchers analyzed the graft itself, it appeared that regular exercise stimulated the grafted muscle to produce certain biochemical signals known to promote the growth of nerves and blood vessels.
“We always think of nerves controlling muscles, but we don’t think about muscles responding to nerves,” says Raman. “So we started to think that stimulating the muscles encouraged nerve growth. And people said maybe that was the case, but there are hundreds of other types of cells in an animal, and it’s very difficult to prove that the nerve is growing more because of the muscle, rather than the immune system or something else that plays a role.
In their new study published in Writing in the journal Advanced Healthcare Materials, the team sought to determine whether muscle exercise had a direct effect on nerve growth, focusing only on muscle and nerve tissue.
The team genetically modified the muscle so that it contracts 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 the act of exercise. Raman previously developed a new gel mat on which to build and exercise muscle tissue. The properties of the gel are such that it can support muscle tissue and prevent it from peeling off when researchers stimulate the muscle to exercise.
DEVELOP YOUR BRAIN: A new study of more than 10,000 people found that regular physical activity is linked to bigger, healthier brains
The team then collected samples of the surrounding solution in which the muscle tissue was being exercised, reasoning that the solution must contain myokines, including growth factors, RNA, and a mixture of other proteins.
“Muscles almost always secrete myokines, but when you exercise them, they make more of them,” says Raman.
The researchers grew the neurons from stem cells taken from mice. As with muscle tissue, neurons were cultured on a similar gel mat. After the neurons were exposed to the myokine mixture, the team observed that they quickly began to grow, four times faster than neurons that had not received the biochemical solution.
“They grow much further and faster, and the effect is quite immediate,” notes Raman.
To take a closer look at how neurons changed in response to exercise-induced myokines, the team performed a genetic analysis, extracting RNA from neurons to see if the myokines induced a change in the expression of certain genes. neuronal.
ALSO GREAT FOR DEPRESSION AND HEART: Exercise reduces heart disease risk by 23% and benefits double for people with depression
“We saw that many genes upregulated in exercise-stimulated neurons were not only related to neuron growth, but also to neuron maturation, their ability to communicate with muscles and other nerves, and to the maturity of the axons,” explains Raman. . “Exercise appears to impact not only the growth of neurons, but also their maturity and proper function.”
The results suggest that the biochemical effects of exercise may promote neuron growth. The group then asked themselves: could the purely physical impacts of exercise have a similar benefit?
“Neurons are physically attached to muscles, so they also stretch and move with the muscle,” explains Raman. “We also wanted to see, even in the absence of biochemical signals from the muscles, could we stretch the neurons back and forth, mimicking the mechanical forces (of exercise), and could that also impact on growth?
It turned out that the biochemical and physical effects of exercise are “equally important.”
WALK: Millions of back pain sufferers can ease their symptoms simply by walking more – for ‘huge benefits’
Now that the group has shown that muscle exercise can promote nerve growth at the cellular level, they plan to study how targeted muscle stimulation can be used to grow and heal damaged nerves, and restore mobility in people living with neurodegenerative disease such as ALS.
“This is just our first step toward understanding and controlling exercise as medicine,” says Raman.
SHARE THE NEWS with fitness gurus on social media…