title: Noninvasive limb remote ischemic preconditioning contributes neuroprotective effects via activation of adenosine A1 receptor and redox status after transient focal cerebral ischemia in rats.
abstract: OBJECTIVE
  To investigate whether activation of adenosine A1 receptor (A1R) through limb remote ischemic preconditioning (RIPC) by a noninvasive tourniquet contribute neuroprotective effects against rat focal cerebral ischemic injury induced by transient middle cerebral artery occlusion (MCAO).
  
  
  METHODS
  One hundred twenty-eight Sprague-Dawley (SD) rats were randomly assigned into eight groups (n=16 each): MCAO, Control, 8-cyclopentyl-1,3-dipropulxanthine (DPCPX, Adenosine A1 receptor antagonist), RIPC, DPCPX+RIPC, Vehicle+RIPC, 2-chloro-N(6)-cyclopentyladenosine (CCPA, Adenosine A1 receptor agonist) and CCPA+DPCPX groups. All animals underwent right middle cerebral artery occlusion (MCAO) for 2 h. Limb RIPC consisted of three cycles of 5-minute ischemia followed by 5-minute reperfusion in right hind-limb by tourniquet application. Neurological deficit scores were evaluated 24 h after reperfusion, and then the infarct volume was assessed with diffusion weighted imaging (DWI) and 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. Inflammation was assessed by serum tumor necrosis factor α (TNF(α)) and NO; oxidative stress was estimated by malondialdehyde (MDA) and 4-hydroxyalkenals (4-HAD), superoxide dismutase (SOD) activity and GSH.
  
  
  RESULTS
  Animals in the RIPC, Vehicle+RIPC and CCPA groups developed lower neurological deficit scores and smaller brain infarct volumes than the Control group (P<0.01). Animals in the DPCPX, DPCPX+RIPC and CCPA+DPCPX groups developed higher neurological deficit scores and larger brain infarct volumes than the RIPC, Vehicle+RIPC and CCPA groups (P<0.01). DPCPX abolished the protective effects of RIPC and CCPA. RIPC or CCPA induced a significant increase in brain MnSOD (manganese SOD) activity and NO generation, and this activity was abolished by DPCPX pretreatment. RIPC or CCPA induced a significant reduction (P<0.05) in the GSH and MDA+4HDA concentration and an accumulation in the GSSG concentration in both compartments (serum and tissue) as compared with the MCAO group.
  
  
  CONCLUSIONS
  The present study demonstrates that limb RIPC induced by noninvasive tourniquet reduces cerebral ischemic injury in rats, and the effect of neuroprotection may depend on the activation of adenosine A1 receptors. CCPA pretreatment can induce delayed ischemic tolerance against cerebral ischemia/reperfusion injury. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation.
authors.affiliation: Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, Shaanxi, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Hu
authors.forename: Hailong
authors.initials: H
authors.lastname: Dong
authors.forename: Haopeng
authors.initials: H
authors.lastname: Zhang
authors.forename: Shiquan
authors.initials: S
authors.lastname: Wang
authors.forename: Lichao
authors.initials: L
authors.lastname: Hou
authors.forename: Shaoyang
authors.initials: S
authors.lastname: Chen
authors.forename: Jinsong
authors.initials: J
authors.lastname: Zhang
authors.forename: Lize
authors.initials: L
authors.lastname: Xiong
mesh_terms: D000241:Adenosine / Q000008:administration & dosage / Q000031:analogs & derivatives; D000704:Analysis of Variance; D000818:Animals; D020520:Brain Infarction / Q000209:etiology / Q000517:prevention & control; D038524:Diffusion Magnetic Resonance Imaging; D004195:Disease Models, Animal; D005121:Extremities / Q000294:innervation*; D005978:Glutathione / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000628:therapy*; D002546:Ischemic Attack, Transient / Q000517:prevention & control*; D019194:Ischemic Preconditioning / Q000379:methods*; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D009422:Nervous System Diseases / Q000209:etiology / Q000517:prevention & control; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D043682:Receptor, Adenosine A1 / Q000378:metabolism*; D012720:Severity of Illness Index; D013482:Superoxide Dismutase / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D014970:Xanthines / Q000008:administration & dosage
chemical_list: D018696:Neuroprotective Agents; D009573:Nitrites; D043682:Receptor, Adenosine A1; D014409:Tumor Necrosis Factor-alpha; D014970:Xanthines; C058394:2-chloro-N(6)cyclopentyladenosine; C051360:1,3-dipropyl-8-cyclopentylxanthine; D013482:Superoxide Dismutase; D005978:Glutathione; D000241:Adenosine