For the first time, a team of researchers has succeeded in filming the process of eliminating dead neurons in the brains of several mice.
Cell death is a natural process. Every day, in our brain, billions of neurons pass from life to death. A brain waste disposal system then gets rid of them, ultimately preventing these toxic corpses from clogging our biological pathways.
Nevertheless, this elimination process that occurs after cell death is still very much misunderstood. To better understand it, the ideal would be to be able to observe it directly in action.
Researchers from the Yale School of Medicine (United States) have managed to capture on video how the brains of mice get rid of these neurons .
"This is the first time the process has been observed in a living mammalian brain", explains the neurologist Jaime Grutzendler, main author of this work.
In this study, researchers focused on a single brain cell each time , using a technique called 2Phatal. Then, using fluorescent markers, they followed the behavior of several glial cells, responsible for cleaning the brain.
Researchers then discovered that three types of glial cells – microgliocytes, astrocytes and NG2 cells – were involved in a coordinated fashion in the cell elimination process.
They observed microglia engulf the body of neurons as well as their main branches (dendrites), while astrocytes targeted the smaller connected dendrites, then eliminated them.
The role of glial cells is still mysterious. Nevertheless, researchers suspect that they may help prevent the spread of dead cell debris.
Another interesting point:it was found that if a glial cell missed a neuron, for whatever reason, other cells could take over to ensure the waste disposal process. For the researchers, it is therefore possible that glial cells can communicate with each other (in a still undetermined way).
Finally, it was pointed out that glial cells from older mice were less efficient to remove dead neuronal cells (about twice as slow). According to the team, this phenomenon could damage the nervous system, and ultimately play an important role in the development of neurodegenerative diseases that occur with age.
The big question is:if we could continue to efficiently eliminate all these dying cells, could we prevent these diseases? We could indeed imagine new treatments capable of supporting this brain cleansing process. It's still far too early to tell. For the time being, this work has only been carried out in mice.
Source
