title: [Role of STAT3 signaling pathway in hypoxic-ischemic brain damage of neonatal rats].
abstract: OBJECTIVE
  To study the role and mechanisms of STAT3 signaling pathway in hypoxic-ischemic brain damage (HIBD) of neonatal rats.
  
  
  METHODS
  Eighty 7-day-old Sprague-Dawley rats were randomly divided into two groups: HI and sham-operated (n=40 each). The rats in the HI group were subjected to right carotid artery ligation and subsequent hypoxia exposure (8% O2) for 2.5 hours, and the rats in the sham-operated group underwent the right carotid artery dissection without subsequent ligation or hypoxia treatment. Brain tissue samples were collected at 4, 6, 8, 12 and 24 hours after operation and hypoxic exposure. Immunohistochemistry and Western blot were used to detect the expression of STAT3, phosphorylated STAT3 (p-STAT3) and vascular endothelial growth factor (VEGF) proteins. TUNEL staining was used to detect apoptotic cells.
  
  
  RESULTS
  No significant difference in STAT3 expression was observed at all time points between the HI and sham-operated groups (P>0.05). Compared with the sham-operated group, the expression of p-STAT3 protein in the HI group was significantly upregulated at 4, 6, 8, 12 hours after operation and hypoxic exposure, and peaked at 6 hours (P<0.01). The VEGF expression in the HI group was higher than that in the sham-operated group at all time points, which peaked at 8 hours (P<0.05). TUNEL staining showed that the apoptotic cells increased significantly in a time-dependent manner compared with the sham-operated group (P<0.01).
  
  
  CONCLUSIONS
  HI may lead to phosphorylation of STAT3 which probably induces the VEGF expression in the brain of neonatal rats. The activated STAT3 signaling pathway may be involved in the apoptosis regulation of nerve cells, and related to apoptosis inhibition of nerve cells.
authors.affiliation: Department of Pediatrics, West China Second University Hospital, Chengdu 610041, China. mdzscu@sina.com.
authors.forename: Rui
authors.initials: R
authors.lastname: Deng
authors.forename: Feng-Yan
authors.initials: FY
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: De-Yuan
authors.initials: DY
authors.lastname: Li
authors.forename: De-Zhi
authors.initials: DZ
authors.lastname: Mu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism*; D008297:Male; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D050796:STAT3 Transcription Factor / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
chemical_list: D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; D042461:Vascular Endothelial Growth Factor A