TOMSK, Nov 24 – RIA Tomsk. With the help of a new non-invasive method, neuroscientists of Tomsk State University (TSU) for the first time in the world were able to trace the death and restoration of nerve cells and axons after a cerebral stroke. The study was conducted on laboratory animals. Details are in the RIA Tomsk review.
As reported on the university website on Tuesday, this project was carried out with the support of the Russian Science Foundation (RSF).
"Terrain relief" of the brain
The new non-invasive method is a diagnostic technology created in the TSU Laboratory for Neurobiology under the supervision of its scientific advisor, professor of the Tomsk State University and University of Washington Vasily Yarnykh. Earlier it was reported that such an approach would provide a holistic picture of changes in the lesion and increase the accuracy of the prognosis of patient rehabilitation.
"Using special procedures for mathematical processing of MRI data, scientists receive maps of myelin - images of the brain reflecting the number of sheaths of nerve fibers in the same way as the terrain is depicted on geographic maps. Myelin maps reveal microscopic changes in brain matter that cannot be detected with traditional MRI", - details are revealed on the university website.
Within the framework of the project, TSU scientists conducted two experiments. In the first, the condition of the animals was monitored for ten days after the stroke. During the second stage, multiple scans of the rodent brain were carried out over three months. In both cases, the scientists looked at what happens to the neurons and axons (processes of nerve cells), along which impulses travel from one nerve cell to another.
At the same time, a quantitative assessment of myelin, the main substance in the composition of the nerve sheaths, was carried out. The correct transfer of information between the cells of the nervous system depends on its state.
"Studies of neuroscientists have shown that after a stroke in the area of the brain where there was a violation of blood supply, neurons and axons die, but some of the axons remain alive, although demyelinated. It also turned out that this process is not irreversible - over time, myelin is restored in the nerve sheaths", - the press service said.
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Upper row: dynamics of myelin changes in rats after stroke. Bottom row: the state of the myelin sheaths of axons: A - normal; B - destroyed after a stroke; С - in the process of recovery, 30 days after the stroke
Versatile connections
According to the results of observations, scientists reported another phenomenon.
"From healthy neurons from intact areas, in which axons have died and therefore connections with other nerve cells is broken, new axons grow. They can pass through the ischemic region, reaching healthy neurons and forming new neural networks. If a new connection is formed, and along the axon nerve impulses begin to pass - this is a signal for the formation of a new myelin sheath", - says the message.
It is noted that the germination of new nerve endings in rats occurs rather quickly - after two to three months.
“Apparently, the new conducting network does not fully reproduce the one that was before the injury, but, nevertheless, the axons are trying to establish the lost connection between the cells”, - head of the TSU Laboratory for Neurobiology Marina Khodanovich is quoted in the message.
According to her, the further task of the project team is to find out how the restoration of the network affects the resumption of various functions: perception, memory, fine motor skills and others. To do this, it is necessary to understand how the structure of the nervous network has changed, and compare this with the restoration of functions.
At a new stage of research, scientists plan to use a combination of two methods of magnetic resonance imaging: MPF-mapping and tractography, which allows to evaluate the pathways of the nervous system.
"This will help to see from the inside the processes of brain recovery after a stroke and compare them with the dynamics of rehabilitation of sensory, motor, cognitive abilities. The new approach is promising both for monitoring the state and for predicting the dynamics and volume of recovery of lost functions", - explains the website.
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Laboratory rats
It is added that neuroscientists also plan to obtain new fundamental data by studying the molecular mechanisms of neuronal and axon repair. Scientists will try to answer many questions for the first time, in particular, to determine how a healthy axon finds its way to the cell with which it needs to establish a connection.
"Researchers expect to find "targets", the impact on which will stimulate the recovery processes and accelerate the return of patients to a normal quality of life", - the TSU press service sums up.