OVER the centuries scientists have been fascinated with the topic of regeneration in lower vertebrate species – and in particular the zebrafish.

These are highly regenerative and can regrow fins which have been amputated, along with other tissues such as retina, spinal cord and heart.

Now, scientists in Edinburgh say fresh insights into how zebrafish repair their damaged nerve connections could help the development of therapies for people with spinal cord injuries.

They have found the immune system plays a key role in helping zebrafish nerve cells to regenerate following an injury, and it is hoped the findings will offer clues for developing treatments which one day could help people to regain movement after injuring their spinal cord.

The study focussed on large immune cells called macrophages, which are vital for the fish to repair damaged connections. Such cells usually help the body to fight off infections, but they also play a key role in wound healing.

Researchers at the University of Edinburgh found that macrophages produce key molecules which dampen inflammation at the spinal injury site. This enables nerve cells to bridge the gap and repair lost connections.

The scientists’ next step will be to understand how these molecules function in humans.

Their study was published in the journal Nature Communications and funded by the Biotechnology and Biological Sciences Research Council. A team from the university’s Centre for Discovery Brain Sciences has established a system to study the complex interactions between immune cells at a spinal injury site and how they contribute to the repair of damaged nerve connections in zebrafish.

Professor Catherina Becker, from the centre, said: “Zebrafish are interesting to us because they can regain full swimming ability after spinal cord injury.

“Our research is focused on understanding the factors involved in this process so that we can look for potential ways of developing treatments for people.”