title: [Effect of M8046 on expression of COX-2/PGE2 in spinal cord and DRG in rats with neuropathic pain].
abstract: OBJECTIVE
  To investigate the effects of glucocorticoid receptor antagonist-M8046 on the behavior and the cyclooxygenase-2/prostaglandin E2( COX-2/PGE2) expression in spinal cord dorsal horn and dorsal root ganglia (DRG) in chronic constrictive injury (CCI) rats.
  
  
  METHODS
  One hundred and forty-four male SD rats were randomly divided into 4 groups, 36 rats in each group: Sham operation group (Sham), chronic constrictive group (CCI), M8046 treated group (M8046) and solvent controlled group (Sc). M8046 3 mg/(kg x d) intraperitoneal injection was given after operation in group M8046. Paw thennal withdrawal (PTWL) and paw mechanical withdrawal threshold (PMWT) of rats were measured on 2 pre-operative and 1, 3, 7, 10, 14 post-operative days. The spinal cord and L15 DRG of the operated side was removed at 3, 7, 14 days after surgery. The change of COX-2 and PGE2 expression was determined by immunohistochemical staining and ELISA separately.
  
  
  RESULTS
  PTWL and PMWT in CCI group were significantly lower than those in Sham group on every post-operative day (P < 0.05). PTWL and PMWT in M8046 group were significantly higher than those in CCI group on 7, 10, 14 post-operative day (P < 0.05). In spinal dorsal horn, the level of COX-2 and PGE2 expression in CCI group was significantly higher than that in Sham group (P < 0.05). M8046 could significantly attenuate the activation of COX-2 and PGE2 induced by CCI (P < 0.05). The expression of COX-2 and PGE2 in DRG was similar to that in spinal dorsal horn.
  
  
  CONCLUSIONS
  The effects of M8046 ameliorate the CCI-induced neuropathic pain may be related to attenuate the expression of COX-2 and PGE2 in spinal cord and DRG.
authors.affiliation: Department of Anesthesiology, the Second Affiliated Hospital, Wenzhou Medical College, Wenzhou 325027, China.
authors.forename: Guo-Kun
authors.initials: GK
authors.lastname: Ou
authors.forename: Rui-Xian
authors.initials: RX
authors.lastname: Wang
authors.forename: Jia-Jia
authors.initials: JJ
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Cao
authors.forename: Qing-Quan
authors.initials: QQ
authors.lastname: Lian
authors.forename: Jun
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009437:Neuralgia / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011965:Receptors, Glucocorticoid / Q000037:antagonists & inhibitors*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011965:Receptors, Glucocorticoid; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D015232:Dinoprostone