Scientists have found a new 'guinea pig' to study how the brain regulates its blood supply. It is not a pig or a rat or any rodent, but a fish—zebrafish.
Neurovascular coupling is an important function of the brain and if it goes wrong, it can cause neurodegenerative conditions such as dementia and stroke. Until now, neurovascular research to measure brain function and blood flow has always been conducted using rodents, which undergo invasive surgery under anaesthetic.
Now, a team of scientists in the UK's Sheffield University has developed the ground breaking method using the 1-2mm long tadpole-like zebrafish larvae which are nearly transparent. Their transparency allows the observation of brain function and blood flow in a non-invasive and completely painless way.
“Understanding neurovascular coupling is essential if we are going to find new treatments for devastating diseases such as dementia and stroke,” said Ms Karishma Chhabria who was part of the team. “We only use animals where no other alternatives are possible and are committed to finding other alternatives. Observing zebrafish is completely painless and non-invasive. This allows a totally new approach for studying brain function.”
The Sheffield research group has already used this zebrafish model to discover a drug which reverses the effect of diabetes on brain function, which is hoped to be taken to clinical trial in the future.
Dr Clare Howarth, the leader of the team, said: “Our neurones have very little energy reserves so when they are deprived of oxygen—which occurs when someone has a stroke—the neurones can die very quickly and there is no way to bring them back. With this new model we were able to observe early biomarkers of when neurovascular coupling goes wrong. In the case of our diabetes research, we were able to observe the effect of a new treatment reversing the effects of too much glucose. The results are really promising and pave the way for further diabetes research in this area using zebrafish.”
Added Tim Chico, professor of Cardiovascular Medicine who was part of the team: “Diabetes has quadrupled in the last decades and has major effects on the heart and brain. We are excited that we have found a way to reverse the effects of high glucose on brain function which, if effective in humans, would be a major advance.”
The work was funded by the National Centre for Replacement, Refinement and Reduction of Animals in Research (NC3Rs). The research is published in the Journal of Cerebral Blood Flow and Metabolism.
