title: [The role of Leptin on neuron apoptosis in mice with cerebral ischemia/reperfusion injury].
abstract: OBJECTIVE
  To study the effect of Leptin on neuron apoptosis in mice with cerebral ischemia injury and its mechanism.
  
  
  METHODS
  Seventy-five mice were randomly divided into three groups. Focal cerebral ischemia/reperfusion injury model in mice was reproduced by middle cerebral artery occlusion for 2 hours followed by reperfusion. In Leptin intervention group mice were given Leptin 1 μg/g during cerebral ischemia by intraperitoneal injection. Mice in the model group were given equal amount of phosphate buffer saline. After reperfusion for 24 hours, the neuron apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. The mRNA and protein expression of apoptosis relative gene caspase-3 and bcl-2 were determined by reverse transcription-polymerase chain reaction (RT-PCR) and immuno histochemistry.
  
  
  RESULTS
  Most of neuron necrosis was observed in cerebral ischemia center in model group. Compared with sham-operation group, neuron apoptosis rate, mRNA and protein expression of caspase-3 and bcl-2 in model group increased significantly [apoptosis rate: (68.65 ± 0.79)% vs. (4.40 ± 0.00)%, caspase-3 mRNA: 2.563 ± 0.250 vs. 0.153 ± 0.020, bcl-2 mRNA: 0.337 ± 0.100 vs. 0.125 ± 0.030, caspase-3 protein (absorbance value, A value): 0.57 ± 0.05 vs. 0.37 ± 0.03, bcl-2 protein (A value): 0.51 ± 0.04 vs. 0.35 ± 0.01, all P<0.01]. The apoptosis rate of penumbra neurons was reduced in Leptin intervention group significantly compared with model group [(42.30 ± 8.45)% vs. (68.65 ± 0.79)%, P<0.01]. Compared with model group, the mRNA and protein expression of caspase-3 in Leptin intervention group were reduced significantly [caspase-3 mRNA: 2.267 ± 0.040 vs. 2.563 ± 0.250, caspase-3 protein (A value): 0.45 ± 0.04 vs. 0.57 ± 0.05, P>0.05 and P<0.01], and the mRNA and protein expression of bcl-2 in Leptin intervention group upregulated significantly [bcl-2 mRNA: 0.662 ± 0.040 vs. 0.337 ± 0.100, bcl-2 protein (A value): 0.76 ± 0.09 vs. 0.51 ± 0.04, both P<0.01].
  
  
  CONCLUSIONS
  Leptin could reduce apoptosis of neurons through down-regulation of the expression of caspase-3 and up-regulation of the expression of bcl-2. The results suggest that Leptin plays a neuroprotective role in cerebral ischemia injury.
authors.affiliation: Research Laboratory of Biochemistry, Basic Medical Institute, General Hospital of PLA, Beijing 100853, China. yan301@263.net
authors.forename: Guang-tao
authors.initials: GT
authors.lastname: Yan
authors.forename: Yi-ling
authors.initials: YL
authors.lastname: Si
authors.forename: Jin-ying
authors.initials: JY
authors.lastname: Zhang
authors.forename: Zi-hui
authors.initials: ZH
authors.lastname: Deng
authors.forename: Hui
authors.initials: H
authors.lastname: Xue
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002545:Brain Ischemia / Q000378:metabolism / Q000473:pathology*; D053148:Caspase 3 / Q000378:metabolism; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology*
chemical_list: D020738:Leptin; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; C052617:Bcl2 protein, mouse; C505409:Casp3 protein, mouse; D053148:Caspase 3