Brillante investigación revela cómo el ejercicio mejora la salud del cerebro con señales químicas

El estudio de las señales químicas de las células musculares que se contraen apunta a formas de mejorar la salud del cerebro con el ejercicio.

Los investigadores de Beckman estudiaron cómo las señales químicas de los músculos contraídos promueven cerebros saludables. Sus hallazgos revelan cómo estas señales ayudan a desarrollar y regular nuevas redes cerebrales, al mismo tiempo que señalan formas de mejorar la salud del cerebro a través del ejercicio.

La actividad física se cita a menudo como un medio para mejorar la salud física y mental. Investigadores del Instituto Beckman de Ciencia y Tecnología Avanzadas han demostrado que también puede mejorar la salud del cerebro de manera más directa. Estudiaron cómo las señales químicas liberadas por los músculos en ejercicio promueven el desarrollo neuronal en el cerebro.

Su trabajo ha sido publicado en la revista neurociencia.

Cuando los músculos se contraen durante el ejercicio, como cuando un bíceps trabaja para levantar un peso pesado, liberan una variedad de compuestos en el torrente sanguíneo. Estos compuestos pueden viajar a diferentes partes del cuerpo, incluido el cerebro. Los investigadores estaban particularmente interesados ​​en cómo el ejercicio podría beneficiar a una parte particular del cerebro llamada hipocampo.

«El hipocampo es un área crucial para el aprendizaje y la memoria y, por lo tanto, para la salud cognitiva», dijo Ki Yun Lee, estudiante de doctorado en ciencias mecánicas e ingeniería en la Universidad de Illinois Urbana-Champaign y autor principal del estudio. Por lo tanto, comprender cómo el ejercicio beneficia al hipocampo podría conducir a tratamientos basados ​​en el ejercicio para una variedad de afecciones, que incluyen[{» attribute=»»>Alzheimer’s disease.

Hippocampal neurons (yellow) surrounded by astrocytes (green) in a cell culture from the study. Image provided by the authors. Credit: Image provided by the study authors: Taher Saif, Justin Rhodes, and Ki Yun Lee

To isolate the chemicals released by contracting muscles and test them on hippocampal neurons, the researchers collected small muscle cell samples from mice and grew them in cell culture dishes in the lab. When the muscle cells matured, they began to contract on their own, releasing their chemical signals into the cell culture.

The research team added the culture, which now contained the chemical signals from the mature muscle cells, to another culture containing hippocampal neurons and other support cells known as astrocytes. Using several measures, including immunofluorescent and calcium imaging to track cell growth and multi-electrode arrays to record neuronal electrical activity, they examined how exposure to these chemical signals affected the hippocampal cells.

The results were striking. Exposure to the chemical signals from contracting muscle cells caused hippocampal neurons to generate larger and more frequent electrical signals — a sign of robust growth and health. Within a few days, the neurons started firing these electrical signals more synchronously, suggesting that the neurons were forming a more mature network together and mimicking the organization of neurons in the brain.

However, the researchers still had questions about how these chemical signals led to growth and development of hippocampal neurons. To uncover more of the pathway linking exercise to better brain health, they next focused on the role of astrocytes in mediating this relationship.

“Astrocytes are the first responders in the brain before the compounds from muscles reach the neurons,” Lee said. Perhaps, then, they played a role in helping neurons respond to these signals.

The researchers found that removing astrocytes from the cell cultures caused the neurons to fire even more electrical signals, suggesting that without the astrocytes, the neurons continued to grow — perhaps to a point where they might become unmanageable.

“Astrocytes play a critical role in mediating the effects of exercise,” Lee said. “By regulating neuronal activity and preventing hyperexcitability of neurons, astrocytes contribute to the balance necessary for optimal brain function.”

Understanding the chemical pathway between muscle contraction and the growth and regulation of hippocampal neurons is just the first step in understanding how exercise helps improve brain health.

“Ultimately, our research may contribute to the development of more effective exercise regimens for cognitive disorders such as Alzheimer’s disease,” Lee said.

Reference: “Astrocyte-mediated Transduction of Muscle Fiber Contractions Synchronizes Hippocampal Neuronal Network Development” by Ki Yun Lee, Justin S. Rhodes and M. Taher A. Saif, 2 February 2023, Neuroscience.
DOI: 10.1016/j.neuroscience.2023.01.028

In addition to Lee, the team also included Beckman faculty members Justin Rhodes, a professor of psychology; and Taher Saif, a professor of mechanical science and engineering and bioengineering.

Funding: NIH/National Institutes of Health, National Science Foundation