Unlike the tissue in other parts of the body, such as the skin, the neuronal tissue in the brain doesn't regenerate after being damaged. It may one day be able to do so, however, with a little help from a new type of hydrogel.
Developed by a team of scientists at Japan's Hokkaido University, the biocompatible polymer gel is made up of equal parts positively and negatively charged monomers. This combination was found to offer the best adhesion for cells.
The scientists adjusted the ratio of crosslinker molecules in the hydrogel to give it a brain-tissue-like stiffness, plus they created tiny pores in it, as cell "nesting" sites. Next, the gel was soaked in a growth factor serum to boost the growth of blood vessels, after which it was surgically implanted in damaged areas of mouse brains.
Three weeks later, it was found that immune cells and neuronal cells from the surrounding brain tissue had migrated into the implanted hydrogel, plus blood vessels had started growing within it. The researchers then injected neural stem cells into the gel.
After a 40-day period, the vast majority of those cells had survived, and some of them had differentiated into neuronal and neuron-maintaining astrocyte cells. Additionally, some of those new neuronal cells had migrated out of the hydrogel and into the surrounding brain tissue, showing how well the material had been integrated into the brain.
It turned out that the timing of the different steps was very important. When the scientists tried implanting the gel and adding the stem cells at the same time, the procedure was unsuccessful.
A paper on the research, which was led by professors Satoshi Tanikawa and Shinya Tanaka, has been published in the journal Scientific Reports.
Scientists at the University of Georgia previously developed a "brain glue" hydrogel of their own, which they successfully used to treat brain injuries in rats.
Source: Hokkaido University
