title: [Dual role of NF-κB and its target gene iNOS in cerebral ischemic tolerance induced by focal ischemic preconditioning].
abstract: OBJECTIVE
  To investigate the effect of focal cerebral ischemic preconditioning on the expression of nuclear factor kappa B (NF-κB) and its target gene inducible nitric oxide synthase (iNOS) and to explore its role in ischemic tolerance in rats.
  
  
  METHODS
  A total of 32 SD rats were divided into 4 groups. The control group received sham surgery (SS) twice only. The IPC + SS group received 10 minutes of ischemic preconditioning (IPC) followed by SS 3 days later. And the other two groups received 2 hours of middle cerebral artery occlusion (MCAO) followed by 22 hours of reperfusion with or without IPC 3 days before. The ultrastructure, NF-κB activation and iNOS mRNA transcription were evaluated in each group by electron microscope, immunohistochemistry staining and reverse transcriptase polymerase chain reaction (RT-PCR) respectively.
  
  
  RESULTS
  (1) In contrast with the SS + SS group, there was a lower NF-κB immunoreactivity (57.3 ± 6.3) and iNOS mRNA level (29.1% ± 3.1%) in the IPC + SS group while no ultrastructural abnormality was identified. (2) The expression of NF-κB/iNOS was down-regulated in the IPC + MCAO group (81.2% ± 7.3%/89.0% ± 5.3%) than in the SS + MCAO group (98.9% ± 9.4%/132.8% ± 7.9%, P < 0.01) with minor ultrastructure abnormality.
  
  
  CONCLUSIONS
  A down-regulated expression of NF-κB/iNOS is a key event in the molecular mechanism of cerebral ischemic tolerance. And the NF-κB/iNOS pathway might play a dual role in endogenous neuroprotection induced by focal IPC.
authors.affiliation: Department of Neurology, Second Affiliated Clinical College in Chengdu, Chongqing Medical University, Third People's Hospital of Chengdu, Chengdu 610031, China. haoyuman@163.com
authors.forename: Yu-man
authors.initials: YM
authors.lastname: Hao
authors.forename: Zu-ming
authors.initials: ZM
authors.lastname: Luo
authors.forename: Dong
authors.initials: D
authors.lastname: Zhou
authors.forename: Li
authors.initials: L
authors.lastname: Gao
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zhang
authors.forename: Zhong
authors.initials: Z
authors.lastname: Zeng
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D019194:Ischemic Preconditioning; D008297:Male; D016328:NF-kappa B / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D014158:Transcription, Genetic
chemical_list: D016328:NF-kappa B; D012333:RNA, Messenger; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat