Xenon prevents inflammation-induced delayed pain hypersensitivity in rats

Rats received an intraplantar carrageenan injection for inducing hind paw inflammation. After 1 h 45 min, they were exposed to medical air (air group), xenon 25% (Xe-25 group) or 50% (Xe-50 group) for 1 h 45 min. Mechanical nociceptive threshold was evaluated on experimental day and once daily for 1 week. Beyond the well-known antinociceptive effect of xenon, the delayed hyperalgesia observed for 4 days after carrageenan injection was strongly reduced in Xe-25 group and totally suppressed in Xe-50 group on the inflamed hind paw. Moreover, delayed hyperalgesia on the noninflamed hind paw was totally suppressed for both the xenon concentrations. These results show that xenon, beyond its antinociceptive effects, may be a fruitful therapeutic strategy to limit the development of pain sensitization after tissue injury.