Scientists have succeeded for the first time in integrating rat neurons into the brains of mice

Biologists from the United States and China have for the first time bred hybrid mice with neurons from two different types.

Some neurons in the brain were replaced with their counterparts in rats. The Columbia University press service reported that the rodent brain may successfully adapt to foreign neurons.

Christine Baldwin, a professor at Columbia University, said: “Our research showed that rat neurons were present in almost all areas of the rat’s brain, which was a big surprise to us. This means that there are relatively few obstacles to the process of transplanting rats into mice.” Thus, using a similar method, we will be able to replace a large number of neuron types in mice with their counterparts from the rat brain.

Baldwin and her colleagues made this discovery as part of an experiment in raising the world's first mice with "hybrid" brains that contain neurons from two different types, but closely related to rodents. In the past, biologists tried to grow hybrid animals whose brains contained two different sets of cells, but all these attempts failed.

Chinese and American researchers were able to solve this problem using the CRISPR/Cas9 genome editor, which allowed scientists to selectively remove part of the embryonic stem cells of mice by destroying the genes DKK1, HESX1, and SIX3, which are responsible for the formation of various brain tissues, and replacing them with similar bodies extracted from rat embryos. This process allowed future neurons to take root in the mice's developing brains and successfully replace the lost cells.

This result of the experiment came as a surprise to biologists, because the brain of rats is larger and develops more slowly than the nervous system of mice. However, the transplanted portions of rat neurons adapted to life inside the mouse brain and accelerated their development. After the mice with the "hybrid" brain were born, they were quite successful in performing the tasks assigned to them, including smell recognition.

The scientist concluded by saying: “At present, scientists are conducting experiments on transplanting stem cells and nerve cells into the brains of patients with epilepsy and Parkinson’s disease, and we do not yet have a clear idea of ​​the extent of the success of this treatment. Creating “hybrid” model organisms will allow us to obtain an answer to "This question is asked much faster than clinical trials allow."