title: [Analgesic Effect and Mechanism of Electroacupuncture on Rats with Chronic Inflammatory Pain].
abstract: OBJECTIVE
  To observe analgesic effect of electroacupuncture ( EA) on rats with chronic inflammatory pain and its regulatory mechanism on ispilateral dorsal root ganglion (DRG) and spinal dorsal horn (SDH) Mas-related G protein-coupled C receptor (MrgprC).
  
  
  METHODS
  Totally 40 healthy male SD rats were divided into 4 groups according to random number table, i.e., the normal (N) group, the model (M) group, the acupuncture (Acu) group, the EA group, 10 rats in each group. The model of chronic inflammatory pain was established by subcutaneous injecting 0. 1 mL complete Freund's adjuvant (CFA) into right hind paw. Paw withdrawal thresholds (PWTs) were measured before modeling, at day 1, 3, 5, 7, and after CFA injection, respectively. Expression levels of MrgprC in ispilateral DRG and SDH were detected by Western blot. The content of bovine adrenal medulla 22 (BAM22) in SDH was detected by immunohistochemical assay.
  
  
  RESULTS
  Compared with N group at each time point, PWTs significantly decreased in M group (P <0. 01). Compared with M group, PWTs significantly increased at day 5 of EA and after EA in EA group (P < 0.05, P < 0.01). Compared with Acu group at each time point, post-EA PWTs significantly increased in the EA group (P < 0.05). Compared with N group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in M group (P < 0.01). Compared with M group, expression of MrgprC in ispilateral DRG and ratio of BAM22 positive cells in ispilateral SDH increased in the EA group (P < 0.05).
  
  
  CONCLUSIONS
  EA had favorable analgesic effect on chronic inflammatory pain induced by CFA, and its mechanism might be possibly associated with up-regulating MrgprC expression in ispilateral DRG and BAM22 content in ispilateral SDH.
authors.forename: Ying-jun
authors.initials: YJ
authors.lastname: Liu
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Jian-qiao
authors.initials: JQ
authors.lastname: Fang
authors.forename: Jing-ruo
authors.initials: JR
authors.lastname: Zhang
authors.forename: Xi-lv
authors.initials: XL
authors.lastname: Chi
authors.forename: Hua-de
authors.initials: HD
authors.lastname: Chen
mesh_terms: D000698:Analgesia; D000818:Animals; D015671:Electroacupuncture; D004745:Enkephalins / Q000378:metabolism; D005620:Freund's Adjuvant; D005727:Ganglia, Spinal / Q000187:drug effects; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy*; D008297:Male; D059408:Pain Management / Q000379:methods*; D010446:Peptide Fragments / Q000378:metabolism; D020671:Posterior Horn Cells / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: C586459:BAM22 peptide; D004745:Enkephalins; D010446:Peptide Fragments; D005620:Freund's Adjuvant