Could Exercise Be the Key to Repairing Damaged Nerves?

A new study reveals how muscle contractions not only strengthen our muscles but also play a crucial role in promoting the growth and regeneration of motor neurons. This discovery expands our understanding of exercise beyond physical well-being and opens the door to new therapies for nerve injuries and neurodegenerative diseases.

The “Muscle Juice” That Nourishes Neurons

When muscles contract, they generate two types of signals:

• Biochemical signals, through the release of myokines, proteins that act as messengers between muscles and other tissues.

• Biomechanical signals, driven by the physical effects of movement.
  

Scientists developed an innovative model that cultivates muscle fibers within a specialized hydrogel. Using controlled stimulation, these fibers release a “muscle juice” rich in myokines. When motor neurons were exposed to this liquid, researchers observed a significant increase in the growth of their axons and dendrites.

Mimicking Muscle Contractions with Magnets

To study the physical effects, researchers created a technique called MAGMA (Matrix-assisted Magnetic Actuation), which uses micromagnets to replicate the mechanical forces of muscle contraction. This type of stimulation promoted neuronal growth in a manner comparable to the biochemical impact of myokines.

A Boost for Regenerative Therapies

In previous studies, the team demonstrated that stimulating muscle grafts in damaged nerve areas restored motor function. These findings underscore the essential role of both chemical and mechanical effects of exercise in fostering neuronal regeneration.

What’s Next?

This work not only validates the potential of exercise as “medicine” for the brain but also provides tools to explore how muscle-to-nerve signaling can be applied to regenerative therapies.

References:

• Bu, A., Afghah, F., Castro, N., Bawa, M., Kohli, S., Shah, K., Rios, B., Butty, V., & Raman, R. (2024). Actuating Extracellular Matrices Decouple the Mechanical and Biochemical Effects of Muscle Contraction on Motor Neurons. Advanced healthcare materials, e2403712. Advance online publication. https://doi.org/10.1002/adhm.202403712
  

• Rousseau, E., Raman, R., Tamir, T., Bu, A., Srinivasan, S., Lynch, N., Langer, R., White, F. M., & Cima, M. J. (2023). Actuated tissue engineered muscle grafts restore functional mobility after volumetric muscle loss. Biomaterials, 302, 122317. https://doi.org/10.1016/j.biomaterials.2023.122317