title: Electroacupuncture pretreatment attenuates cerebral ischemic injury through α7 nicotinic acetylcholine receptor-mediated inhibition of high-mobility group box 1 release in rats.
abstract: BACKGROUND
  We have previously reported that electroacupuncture (EA) pretreatment induced tolerance against cerebral ischemic injury, but the mechanisms underlying this effect of EA are unknown. In this study, we assessed the effect of EA pretreatment on the expression of α7 nicotinic acetylcholine receptors (α7nAChR), using the ischemia-reperfusion model of focal cerebral ischemia in rats. Further, we investigated the role of high mobility group box 1 (HMGB1) in neuroprotection mediated by the α7nAChR and EA.
  
  
  METHODS
  Rats were treated with EA at the acupoint "Baihui (GV 20)" 24 h before focal cerebral ischemia which was induced for 120 min by middle cerebral artery occlusion. Neurobehavioral scores, infarction volumes, neuronal apoptosis, and HMGB1 levels were evaluated after reperfusion. The α7nAChR agonist PHA-543613 and the antagonist α-bungarotoxin (α-BGT) were used to investigate the role of the α7nAChR in mediating neuroprotective effects. The roles of the α7nAChR and HMGB1 release in neuroprotection were further tested in neuronal cultures exposed to oxygen and glucose deprivation (OGD).
  
  
  RESULTS
  Our results showed that the expression of α7nAChR was significantly decreased after reperfusion. EA pretreatment prevented the reduction in neuronal expression of α7nAChR after reperfusion in the ischemic penumbra. Pretreatment with PHA-543613 afforded neuroprotective effects against ischemic damage. Moreover, EA pretreatment reduced infarct volume, improved neurological outcome, inhibited neuronal apoptosis and HMGB1 release following reperfusion, and the beneficial effects were attenuated by α-BGT. The HMGB1 levels in plasma and the penumbral brain tissue were correlated with the number of apoptotic neurons in the ischemic penumbra. Furthermore, OGD in cultured neurons triggered HMGB1 release into the culture medium, and this effect was efficiently suppressed by PHA-543,613. Pretreatment with α-BGT reversed the inhibitory effect of PHA-543,613 on HMGB1 release.
  
  
  CONCLUSIONS
  These data demonstrate that EA pretreatment strongly protects the brain against transient cerebral ischemic injury, and inhibits HMGB1 release through α7nAChR activation in rats. These findings suggest the novel potential for stroke interventions harnessing the anti-inflammatory effects of α7nAChR activation, through acupuncture or pharmacological strategies.
authors.affiliation: Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China. wangqiang@fmmu.edu.cn
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.forename: Qianzi
authors.initials: Q
authors.lastname: Yang
authors.forename: Xuying
authors.initials: X
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Xu
authors.forename: Yi
authors.initials: Y
authors.lastname: Huang
authors.forename: Qiaomei
authors.initials: Q
authors.lastname: Zhang
authors.forename: Xingchun
authors.initials: X
authors.lastname: Gou
authors.forename: Shaoyang
authors.initials: S
authors.lastname: Chen
authors.forename: Lize
authors.initials: L
authors.lastname: Xiong
mesh_terms: D000818:Animals; D001930:Brain Injuries / Q000517:prevention & control*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000627:therapeutic use; D002038:Bungarotoxins / Q000494:pharmacology; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D002544:Cerebral Infarction / Q000209:etiology / Q000517:prevention & control; D004195:Disease Models, Animal; D015671:Electroacupuncture / Q000379:methods*; D004622:Embryo, Mammalian; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000172:deficiency; D024243:HMGB1 Protein / Q000378:metabolism*; D000860:Hypoxia / Q000628:therapy; D020287:In Situ Nick-End Labeling; D020244:Infarction, Middle Cerebral Artery / Q000150:complications; D007276:Injections, Intraventricular; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009474:Neurons / Q000187:drug effects; D018696:Neuroprotective Agents / Q000627:therapeutic use; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011812:Quinuclidines / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013778:Tetrazolium Salts; D013844:Thiazoles; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D002038:Bungarotoxins; C579165:Chrna7 protein, rat; D024243:HMGB1 Protein; C513163:N-(1-azabicyclo(2.2.2)oct-3-yl)furo(2,3-c)pyridine-5-carboxamide; D018696:Neuroprotective Agents; D011812:Quinuclidines; D011978:Receptors, Nicotinic; D013778:Tetrazolium Salts; D013844:Thiazoles; D064569:alpha7 Nicotinic Acetylcholine Receptor; D007770:L-Lactate Dehydrogenase; D010751:Phosphopyruvate Hydratase; C022616:thiazolyl blue; D005947:Glucose