A new study has affirmed the anesthetic drug xenon can help prevent long-term damage associated with traumatic brain injury (TBI). The researchers, from Imperial College London and Johannes Gutenberg University Mainz, have effectively demonstrated in mice that if xenon is administered within a few hours of a TBI it can prevent brain tissue damage that would result in long-term cognitive problems.

Xenon is a noble gas that has been safely used as a human anesthetic for decades. Previous research has shown the gas to have a neuroprotective property in animals subjected to a controlled cortical impact. The latest research set out to explore whether xenon's neuroprotective capacity has long-term effects following a TBI.

The study tracked three different animal groups: those given a TBI followed by a placebo gas, those given a TBI followed by xenon gas, and a healthy control with no TBI. An expansive 20 month follow-up period allowed the researchers to examine whether the xenon treatment reduced long-term damage resulting from the TBI and the conclusions were incredibly promising.

While those animals with a TBI but no xenon treatment ultimately developed late-life cognitive damage, the xenon-treated mice seemed to be protected from this long-term decline. The xenon group displayed similar life expectancy to the healthy control group, and posthumous brain examinations revealed the xenon treatment lowered long-term brain inflammation and neurodegeneration in the hippocampus.

"Xenon appears to act in a variety of ways, but one of the most likely mechanisms to explain its protective effects on brain tissue is by inhibiting receptors in the brain known as NMDA receptors, that become over-activated following a brain injury," explains Rita Campos-Pires, lead author on the study.

The exciting prospect raised by the research is that xenon could be administered to human patients in the short period of time following an acute TBI, helping prevent long-term damage that would result from the injury. Prior work from the same research team suggests the beneficial effects of xenon can be established if administered within around three hours of the initial brain injury.

This means first responders, or emergency rooms, could be equipped with xenon gas as a preventative treatment when patients appear with brain injuries. As xenon has already established a positive safety profile in humans, doctors know how to best administer the gas and are aware of its few side effects.

"We have looked at very long-term outcomes, up to 20 months after TBI in mice," corresponding author Robert Dickinson explains. "This is very rarely done in animal studies and is equivalent to following up human TBI patients until their 80s. The finding that only a short treatment with xenon can have beneficial effects on cognition, survival, and brain damage almost two years later suggests that xenon might in future prevent cognitive decline and improve survival in human TBI patients."

The new research was published in the British Journal of Anaesthesia.