title: Effect of electroacupuncture on the pathomorphology of the sciatic nerve and the sensitization of P2X₃ receptors in the dorsal root ganglion in rats with chronic constrictive injury.
abstract: OBJECTIVE
  To explore the effect of electroacupuncture (EA) on the pathomorphology of the sciatic nerve and the role of P2X3 receptors in EA analgesia.
  
  
  METHODS
  The chronic constriction injury (CCI) model was adopted in this study. A total of 32 rats were randomly divided into four groups: sham CCI, CCI, CCI plus contralateral EA (CCI + conEA) and CCI plus ipsilateral EA (CCI + ipsEA). Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured. EA began at day 7 after the CCI operation and was applied to the Zusanli (ST 36) and Yanglingquan acupoints (GB 34). At day 14, the pathomorphologic changes of the operated sciatic nerve were demonstrated by hematoxylin and eosin staining. In addition, dorsal root ganglion (DRG) neurons isolated from rats were examined by electrophysiological recording to determine if the P2X3 receptor agonists, adenosine 5'-triphosphate disodium (ATP) and α,β-methylen-ATP (α,β-meATP) evoked inward currents.
  
  
  RESULTS
  Pain thresholds in the CCI group were obviously decreased post CCI surgery (P<0.01). In the EA groups, thermal and mechanical threshold values were increased after the last EA treatment (P<0.05, P<0.01). There was no significant difference in light microscopic examination among the four groups (P>0.05). Current amplitude after application of ATP and α,β-meATP in DRG neurons were much larger in the CCI group compared to those obtained in sham CCI (P<0.05). ATP and α, β-meATP invoked amplitudes in the CCI + EA groups were reduced. There was no signififi cant difference between the CCI + conEA group and the CCI + ipsEA group (P>0.05).
  
  
  CONCLUSIONS
  EA analgesia may be mediated by decreasing the response of P2X3 receptors to the agonists ATP and α,β-meATP in the DRG of rats with CCI. No pathological changes of the sciatic nerve of rats were observed after EA treatment.
authors.affiliation: Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang Province 325027, China.
authors.forename: Rui-Dong
authors.initials: RD
authors.lastname: Cheng
authors.forename: Wen-Zhan
authors.initials: WZ
authors.lastname: Tu
authors.forename: Wan-Sheng
authors.initials: WS
authors.lastname: Wang
authors.forename: En-Mao
authors.initials: EM
authors.lastname: Zou
authors.forename: Fen
authors.initials: F
authors.lastname: Cao
authors.forename: Bo
authors.initials: B
authors.lastname: Cheng
authors.forename: Jie-Zhi
authors.initials: JZ
authors.lastname: Wang
authors.forename: Yong-Xia
authors.initials: YX
authors.lastname: Jiang
authors.forename: Song-He
authors.initials: SH
authors.lastname: Jiang
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D003251:Constriction, Pathologic; D015671:Electroacupuncture; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D006930:Hyperalgesia / Q000473:pathology; D015640:Ion Channel Gating / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D058477:Receptors, Purinergic P2X3 / Q000378:metabolism*; D012584:Sciatic Nerve / Q000293:injuries* / Q000378:metabolism / Q000473:pathology*; D013194:Staining and Labeling
chemical_list: D058477:Receptors, Purinergic P2X3; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate