title: [Effect of vitamin E and selenium deficiency on esophageal tumorigenesis and its oxidative stress mechanism].
abstract: OBJECTIVE
  To explore the effect of vitamin E (VE) and selenium (Se) deficiency on esophageal tumorigenesis and its oxidative stress mechanism.
  
  
  METHODS
  110 male F344 rats were randomly divided into 3 groups: VE/Se deficient group (group A), VE/Se normal group (group B) and control group (group C). Animals in group A and group B were subcutaneously injected with N-nitrosomethylbenzylamine (NMBzA) at the dosage of 0.35 mg/kg BW, 3 times per week for 5 weeks. Control group was given the solvent 20% DMSO as negative control. Animals in group A were fed with low-VE/Se diet (46IU/kg VE, 0.05 mg/kg Se), animals in group B and C were fed with normal diet (80IU/kg VE, 0.15 mg/kg Se). Animals were sacrificed to perform macroscopic observation and pathologic inspection at the 25th week of the experiment. Plasma VE level was determined by high-performance liquid chromatography, and Se level was determined by fluorescence method. Cell proliferation and DNA damage in esophagus were detected through immunohistochemistry of BrdU and 8-OH-dG, respectively. Glutathione peroxidase (GPX) and glutathione transferase (GST) activities in plasma, esophagus and liver were analyzed by using test kits.
  
  
  RESULTS
  VE/Se levels of group A were significantly lower than those of group B, the later were slightly lower than those of group C. Visible tumor incidence, tumor multiplicity and pathologic lesions in group A were all significantly more than those in group B. Comparing with group B, cell proliferation and 8-OH-dG levels were also significantly increased in group A. GPX and GST activities in plasma, esophagus and liver of group A were significantly higher than those of group B.
  
  
  CONCLUSIONS
  Vitamin E and selenium deficiency significantly promoted the NMBzA-induced esophageal tumorigenesis. Oxidative stress and DNA damage may be one of the critical routes by which NMBzA induces carcinogenesis in rat esophagus.
authors.affiliation: Institute of Nutrition and Food Safety, Chinese Center for Disease Control and Prevention, Beijing 100021, China. yanghui813@126.com
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.forename: Yongning
authors.initials: Y
authors.lastname: Li
authors.forename: Jin
authors.initials: J
authors.lastname: Fang
authors.forename: Xudong
authors.initials: X
authors.lastname: Jia
authors.forename: Ning
authors.initials: N
authors.lastname: Li
mesh_terms: D000818:Animals; D004128:Dimethylnitrosamine / Q000031:analogs & derivatives; D004938:Esophageal Neoplasms / Q000139:chemically induced / Q000209:etiology* / Q000473:pathology*; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D011916:Rats, Inbred F344; D012643:Selenium / Q000008:administration & dosage / Q000172:deficiency*; D014810:Vitamin E / Q000008:administration & dosage; D014811:Vitamin E Deficiency
chemical_list: D014810:Vitamin E; C014707:nitrosobenzylmethylamine; D012643:Selenium; D004128:Dimethylnitrosamine