A study on the zebrafish suggests that the body might be using hydrogen peroxide as an envoy that marshals troops of healing cells to wounded tissue.
Timothy Mitchison of Harvard Medical School and Thomas Look of Dana Farber Cancer Institute have observed that when the tail fins of these creatures are injured, a burst of hydrogen peroxide is released from the wound and into the surrounding tissue.
The researchers say that teams of rescue-working white blood cells respond to this chemical herald, crawl to the site of damage, and get to work.
"We've known for quite some time that when the body is wounded, white blood cells show up, and it's really a spectacular piece of biology because these cells detect the wound at some distance. But we haven't known what they're responding to. We do know something about what summons white blood cells to areas that are chronically inflamed, but in the case of an isolated physical wound, we haven't really known what the signal is," Nature magazine quoted Mitchison as saying.
For their study, the researchers inserted a gene engineered to change colour in the presence of hydrogen peroxide into zebrafish embryos.
When the researcher disabled a protein that was previously discovered to produce hydrogen peroxide in the human thyroid gland, they observed that not only did hydrogen peroxide not appear at the wound site, but white blood cells also failed to respond to the injury.
"This was our real eureka! moment. We weren't too surprised that we could block hydrogen peroxide production through this technique, but what we didn't expect at all was that white blood cells wouldn't respond. This proved that the white blood cells needed hydrogen peroxide to sense the wound, and move towards it," said Niethammer.
The researchers say that their findings offer something of a conceptual shift in how to view human conditions where hydrogen peroxide plays a role.