title: Protection of ischemic postconditioning against neuronal apoptosis induced by transient focal ischemia is associated with attenuation of NF-κB/p65 activation.
abstract: OBJECTIVE
  Accumulating evidences have demonstrated that nuclear factor κB/p65 plays a protective role in the protection of ischemic preconditioning and detrimental role in lethal ischemia-induced programmed cell death including apoptosis and autophagic death. However, its role in the protection of ischemic postconditioning is still unclear.
  
  
  METHODS
  Rat MCAO model was used to produce transient focal ischemia. The procedure of ischemic postconditioning consisted of three cycles of 30 seconds reperfusion/reocclusion of MCA. The volume of cerebral infarction was measured by TTC staining and neuronal apoptosis was detected by TUNEL staining. Western blotting was used to analyze the changes in protein levels of Caspase-3, NF-κB/p65, phosphor- NF-κB/p65, IκBα, phosphor- IκBα, Noxa, Bim and Bax between rats treated with and without ischemic postconditioning. Laser scanning confocal microscopy was used to examine the distribution of NF-κB/p65 and Noxa.
  
  
  RESULTS
  Ischemic postconditioning made transient focal ischemia-induced infarct volume decrease obviously from 38.6% ± 5.8% to 23.5% ± 4.3%, and apoptosis rate reduce significantly from 46.5% ± 6.2 to 29.6% ± 5.3% at reperfusion 24 h following 2 h focal cerebral ischemia. Western blotting analysis showed that ischemic postconditioning suppressed markedly the reduction of NF-κB/p65 in cytoplasm, but elevated its content in nucleus either at reperfusion 6 h or 24 h. Moreover, the decrease of IκBα and the increase of phosphorylated IκBα and phosphorylated NF-κB/p65 at indicated reperfusion time were reversed by ischemic postconditioning. Correspondingly, proapoptotic proteins Caspase-3, cleaved Caspase-3, Noxa, Bim and Bax were all mitigated significantly by ischemic postconditioning. Confocal microscopy revealed that ischemic postconditioning not only attenuated ischemia-induced translocation of NF-κB/p65 from neuronal cytoplasm to nucleus, but also inhibited the abnormal expression of proapoptotic protein Noxa within neurons.
  
  
  CONCLUSIONS
  We demonstrated in this study that the protection of ischemic postconditioning on neuronal apoptosis caused by transient focal ischemia is associated with attenuation of the activation of NF-κB/p65 in neurons.
authors.affiliation: Department of Pediatrics, First hospital of Jilin University, Changchun, China; Neuroscience Research Center, First hospital of Jilin University, Changchun, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Neurosurgery, First hospital of Jilin University, Changchun, China.
authors.forename: Yongxin
authors.initials: Y
authors.lastname: Luan
authors.affiliation: Department of Neurosurgery, First hospital of Jilin University, Changchun, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Lu
authors.affiliation: Department of Pediatrics, First hospital of Jilin University, Changchun, China.
authors.forename: Hongbo
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Neurosurgery, First hospital of Jilin University, Changchun, China; Neuroscience Research Center, First hospital of Jilin University, Changchun, China.
authors.forename: Yi-nan
authors.initials: YN
authors.lastname: Luo
authors.affiliation: Department of Neurosurgery, First hospital of Jilin University, Changchun, China; Neuroscience Research Center, First hospital of Jilin University, Changchun, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Ge
mesh_terms: D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D001921:Brain / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004195:Disease Models, Animal; D020672:I-kappa B Proteins / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology*; D057775:Ischemic Postconditioning; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D010766:Phosphorylation; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D051996:Transcription Factor RelA / Q000378:metabolism*; D015854:Up-Regulation; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606778:Bcl2l11 protein, rat; D020672:I-kappa B Proteins; D008565:Membrane Proteins; C000606206:Nfkbia protein, rat; C539472:Pmaip1 protein, rat; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051996:Transcription Factor RelA; D051028:bcl-2-Associated X Protein; D000072000:NF-KappaB Inhibitor alpha; D053148:Caspase 3