Hyperbaric oxygen therapy attenuates neuropathic hyperalgesia in rats and idiopathic trigeminal neuralgia in patients

Abstract

Background: Neuropathic pain after nerve injury is severe and intractable, and current drug and non-drug therapies offer very limited pain relief. Hyperbaric oxygen (HBO2) has been clinically used for protection of the nervous system after acute injury. We investigated whether HBO2 treatment could prevent and/or attenuate neuropathic pain in animals and in patients. Methods: Mechanical allodynia and thermal hyperalgesia and neurochemical alterations of neuropathic pain were analysed in male, adult, Sprague-Dawley rats with sciatic nerve injury. Clinical trials were conducted in patients with idiopathic trigeminal neuralgia. Results: Repetitive HBO2 treatment [a combination of pressure at 3 atmosphere absolute (ATA) and pure oxygen] greatly inhibited behavioural signs of neuropathic pain manifested as thermal hyperalgesia and mechanical allodynia. Such an HBO2 treatment also inhibited nerve injury-induced induction of c-Fos and activation of astrocytes and increased phosphorylation of NR2B receptor and the subsequent Ca 2+-dependent signals in rats. Neither high pressure (up to 3 ATA) nor pure oxygen alone resulted in analgesic effect. In clinical trials, one course of HBO2 therapy (10 consecutive days) produced a rapid-onset, dose-dependent and long-lasting analgesic effects evidenced by the decreased doses of carbamazepine required for keeping patient pain at a minimum and decreased scores of visual analogue scales, which was used for patient's self-evaluation. Conclusions: These findings support that HBO2 therapy is an effective approach for treating neuropathic pain in both animals and human beings and suggest that neural protection, anti-inflammation and inhibition of nerve injury-induced altered neural activity may contribute to the analgesic effect of HBO2 therapy.

Effect of intermittent normobaric hyperoxia for treatment of neuropathic pain in Chinese patients with spinal cord injury

“…While 1 h treatment did not reach significant difference compared with treatment with air. Gu et al 13 reported that treatment with pure oxygen for 70 min for seven consecutive days did not significantly alter the increased thermal sensitivity in neuropathic rats. This result was accordance with ours in SCI patients with neuropathic pain.…”

“…On the GPIC results, 4h per day InHO produced analgesic effect in 42.9% patients, which was o1h hyperbaric oxygen treatment (60-75%). 13 To assess some aspect of quality of life scales, SF-36ww and PGIC were used. Significant difference was found only at day 14 in SF-36ww pain scores and PGIC results, which was accordance with the result of VAS scores.…”

“…In study group 1 (A group), patients were exposed to air for the first 3 h and then pure oxygen for 1 h via non-rebreathing reservoir mask for an hour at a rate of 7 l min − 1 . 13,16 In study group 2 (B group), patients were exposed to pure oxygen for 4 h at the same rate. 21,22 In control group, patients were exposed to air for 4 h via nonrebreathing reservoir mask.…”

“…Non-pharmacological treatments such as physical therapy, relaxation, hyperbaric oxygen and acupuncture are suggested. [8][9][10][11][12][13] Oxygen therapy has been clinically used for the treatment of chronic obstructive pulmonary disease and severe oxygen desaturation. Recent researches have reported that oxygen therapy appears to be effective in the pain management and show same effectiveness as hyperbaric oxygen.…”

“…Recent researches have reported that oxygen therapy appears to be effective in the pain management and show same effectiveness as hyperbaric oxygen. [14][15][16] Though studies have revealed the analgesic effect of hyperbaric oxygen in both rats and human with neuropathic pain, 13,[17][18][19] costs and poor availability limit the use of hyperbaric oxygen. These prompt us to investigate the effect of intermittent normobaric hyperoxia (InHO) in the treatment of neuropathic pain.…”