Hyperbaric oxygen treatment decreases pain in two nerve injury models

Hyperbaric oxygen (HBO) treatment has been used clinically to treat a variety of ailments, including severe burns and carbon monoxide poisoning, and in research settings has produced promising results when used to treat animal models of inflammatory pain. However, studies examining neuropathic pain or nerve injury models have been limited to physiological assessments and not whether the pain condition improves. The purpose of this study was to evaluate the effect of HBO on two common models of neuropathic pain, L5 ligation and chronic constriction injury (CCI) of the sciatic nerve. Following surgical manipulations, animals demonstrating mechanical hyperalgesia were randomly assigned to either HBO treatment or control for 90min treatment sessions, after which mechanical sensitivity was assessed at 15min and 6h post. Daily HBO sessions, with assessments 15min post-treatment, continued for two weeks, followed by 5 days of assessment only. The results indicated that both models demonstrated significant improvement in response to treatment over the course of the two-week period, with CCI animals recovering more quickly and maintaining this recovery throughout the post-treatment period. Hyperbaric oxygen treatment appears to be successful in relieving neuropathic pain for an extended period of time, and future research should be aimed at investigating the precise mechanisms underlying this positive effect.