title: Cellular sources of cyclooxygenase-1 and -2 up-regulation in the spinal dorsal horn after spinal nerve ligation.
abstract: OBJECTIVE
  Recent studies suggested that the development of neuropathic pain associated with neural injury may be partly due to up-regulation of cyclooxygenase (COX) in the central nervous system. However, the cellular sources of COX-1 and COX-2 up-regulation following nerve injury are unclear.
  
  
  METHODS
  We investigated the spinal cellular sources of COX-1 and COX-2 in association with allodynia following L5 spinal nerve ligation (SNL).
  
  
  RESULTS
  Post-SNL pain-related behaviour was shown by increased sensitivity to mechanical stimulation. There was a significant increase in both COX-1 and COX-2 immunoreactivity (P < 0.01) on the ipsilateral side of spinal dorsal horn. Double immunofluorescence labelling demonstrated that COX-1 immunoreactive cells colocalized chiefly with dorsal horn neuronal nuclei and microglia, whereas COX-2 was expressed in neuronal cytoplasm.
  
  
  CONCLUSIONS
  These findings demonstrate that while spinal dorsal horn neurones are important source of COX-1 and COX-2 after nerve injury, microglia also contribute to the pathogenesis of neuropathic pain, partly by producing additional COX-1.
authors.affiliation: School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China.
authors.forename: Yee Man
authors.initials: YM
authors.lastname: Lau
authors.forename: Shing Chau
authors.initials: SC
authors.lastname: Wong
authors.forename: Sin Wah
authors.initials: SW
authors.lastname: Tsang
authors.forename: Wai Kit
authors.initials: WK
authors.lastname: Lau
authors.forename: Ai Ping
authors.initials: AP
authors.lastname: Lu
authors.forename: HongQi
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000818:Animals; D051545:Cyclooxygenase 1 / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D006930:Hyperalgesia / Q000201:enzymology; D008026:Ligation; D008297:Male; D009437:Neuralgia / Q000201:enzymology*; D009457:Neuroglia / Q000201:enzymology*; D009474:Neurons / Q000201:enzymology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D066148:Spinal Cord Dorsal Horn / Q000201:enzymology*; D013127:Spinal Nerves / Q000293:injuries; D015854:Up-Regulation
chemical_list: D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2
keywords: COX; astrocyte; microglia; neurone; neuropathic pain; spinal cord