title: Hyperbaric oxygenation treatment alleviates CCI-induced neuropathic pain and decreases spinal apoptosis.
abstract: BACKGROUND
  Increased apoptotic changes in the spinal cord may be responsible for the development of chronic constriction injury (CCI)-induced neuropathic pain. We previously reported the beneficial effect of hyperbaric oxygen (HBO) in the treatment of CCI-induced neuropathic pain. In this study, we tested our hypotheses that HBO may achieve its beneficial effect by inhibiting CCI-induced proapoptosis gene expression and apoptosis in the spinal cord.
  
  
  METHODS
  Male rats were randomized into: SHAM, CCI and CCI + HBO groups. Mechanical hyperalgesia was tested daily following surgery. CCI + HBO rats were treated with HBO for 1 h daily. At 3 days post-CCI, the expression of tumour necrosis factor (TNF)-α and caspase-3 genes was detected. At 7 days post-CCI, apoptotic cells in the spinal cord were detected.
  
  
  RESULTS
  Three days post-CCI, mechanical allodynia had developed in the ipsilateral paw compared with SHAM animals. HBO significantly alleviated CCI-induced mechanical allodynia. In comparison with SHAM, CCI-induced neuropathic pain was associated with higher mRNA levels of TNF-α and caspase-3. HBO significantly decreased CCI-induced mRNA levels of TNF-α and caspase-3. CCI-induced neuropathic pain was also associated with more apoptotic cells in the spinal cord 7 days post-CCI. HBO significantly reduced CCI-induced apoptosis to the level of SHAM animals.
  
  
  CONCLUSIONS
  Overly expressed proapoptosis genes, and subsequent increase in spinal apoptotic cells, seem to contribute to the development of CCI-induced neuropathic pain. The inhibitory role of HBO on spinal proapoptosis genes and apoptotic changes may contribute to its beneficial effect on CCI-induced neuropathic pain.
authors.affiliation: Department of Anesthesiology, SUNY Upstate Medical University, Syracuse, USA.
authors.forename: Q
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Department of Anesthesiology, SUNY Upstate Medical University, Syracuse, USA.
authors.forename: L
authors.initials: L
authors.lastname: Fang
authors.affiliation: Department of Anesthesiology, SUNY Upstate Medical University, Syracuse, USA.
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Anaesthesiology, Upstate Comprehensive Pain Medicine, Syracuse, USA.
authors.forename: S
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Department of Anesthesiology, SUNY Upstate Medical University, Syracuse, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis; D001522:Behavior, Animal; D053148:Caspase 3 / Q000096:biosynthesis / Q000235:genetics; D003251:Constriction, Pathologic / Q000150:complications*; D006930:Hyperalgesia / Q000523:psychology / Q000628:therapy; D006931:Hyperbaric Oxygenation; D008297:Male; D009437:Neuralgia / Q000209:etiology / Q000523:psychology / Q000628:therapy*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000235:genetics
chemical_list: D051017:Apoptosis Regulatory Proteins; D014409:Tumor Necrosis Factor-alpha; D053148:Caspase 3