title: Radiation induced COX-2 expression and mutagenesis at non-targeted lung tissues of gpt delta transgenic mice.
abstract: BACKGROUND
  Although radiation-induced bystander effects have been confirmed using a variety of endpoints, the mechanism(s) underlying these effects are not well understood, especially for in vivo study.
  
  
  METHODS
  A 1-cm(2) area (1 cm × 1 cm) in the lower abdominal region of gpt delta transgenic mice was irradiated with 5 Gy of 300 keV X-rays, and changes in out-of-field lung and liver were observed.
  
  
  RESULTS
  Compared with sham-treated controls, the Spi(-) mutation frequency increased 2.4-fold in non-targeted lung tissues at 24 h after partial body irradiation (PBIR). Consistent with dramatic Cyclooxygenase 2 (COX-2) induction in the non-targeted bronchial epithelial cells, increasing levels of prostaglandin, together with 8-hydroxydeoxyguanosine, in the out-of-field lung tissues were observed after PBIR. In addition, DNA double-strand breaks and apoptosis were induced in bystander lung tissues after PBIR.
  
  
  CONCLUSIONS
  The PBIR induces DNA damage and mutagenesis in non-targeted lung tissues, especially in bronchial epithelial cells, and COX-2 has an essential role in bystander mutagenesis.
authors: Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA.
authors: Y
authors: Y
authors: Chai
authors: G M
authors: GM
authors: Calaf
authors: H
authors: H
authors: Zhou
authors: S A
authors: SA
authors: Ghandhi
authors: C D
authors: CD
authors: Elliston
authors: G
authors: G
authors: Wen
authors: T
authors: T
authors: Nohmi
authors: S A
authors: SA
authors: Amundson
authors: T K
authors: TK
authors: Hei
mesh_terms: D000005:Abdomen / Q000528:radiation effects; D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D024201:Bystander Effect; D051546:Cyclooxygenase 2 / Q000378:metabolism* / Q000528:radiation effects; D004249:DNA Damage; D015232:Dinoprostone / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics*; D005260:Female; D008099:Liver / Q000528:radiation effects*; D008168:Lung / Q000528:radiation effects; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D016296:Mutagenesis; D010430:Pentosyltransferases / Q000235:genetics*; D014965:X-Rays
chemical_list: D029968:Escherichia coli Proteins; D051546:Cyclooxygenase 2; D010430:Pentosyltransferases; C071962:Gpt protein, E coli; D015232:Dinoprostone