Neutrophils are a type of white blood cell and integral to the immune system. They are known to attack germs in case of infection but a new study now shows that they also help heal the body. The study shows that some neutrophils may help heal the brain after a stroke.

Researchers at the University of Texas Health Science Center at Houston conducted a study to show that two neutrophil-related proteins may play critical roles in protecting the brain from stroke-induced damage in intracerebral haemorrhage, a form of stroke caused by ruptured blood vessels. The study suggests these proteins could be used as treatments for intracerebral haemorrhage.

Intracerebral haemorrhages account for 10% to 15% of all strokes and often lead to death or long-term disability. So far, there are no effective medicines for this kind of stroke, the researchers said.

In this study published in Nature Communications, the researchers injected the protein interleukin-27, which controls the activity of immune cells, into mice that suffered strokes. Days later, the treated mice had better mobility, and could walk, stretch their limbs and navigate holes in a floor. They also has less brain damage. In contrast, injections of an antibody that blocked natural IL-27 activity slowed recovery.

The researchers suggested that the brain secretes high levels of IL-27 after a haemorrhagic stroke.This causes a wave of neutrophils carrying more of the protein to arrive at the site of the stroke so perform healing functions.

The researchers also showed an iron-binding protein called lactoferrin may protect the brain from intracerebral haemorrhagic strokes. They found that mice and rats injected with lactoferrin 30 minutes after haemorrhages recovered faster and had reduced brain damage compared to animals given placebos.The researchers are now working towards testing lactoferrin treatment in patients.