title: X-rays affect the expression of genes involved in angiogenesis.
abstract: BACKGROUND
  We have previously shown, using the chicken embryo chorioallantoic membrane (CAM) model of in vivo angiogenesis, that X-rays act on the extracellular matrix and enhance normal and tumor-induced angiogenesis. In the present work, we studied the effect of X-rays on the gene expression of three proteins that are important regulators of angiogenesis: vascular endothelial growth factor (VEGF), heparin affin regulatory peptide (HARP) and inducible nitric oxide synthase (iNOS).
  
  
  METHODS
  An area of 1 cm2 of the CAM, restricted by a plastic ring was irradiated at room temperature. The expression of the genes was studied using RT-PCR and the amounts of the mRNAs were quantified using image analysis of the corresponding agarose gels of the RT-PCR products.
  
  
  RESULTS
  VEGF mRNA was decreased 6 h after irradiation. However, at later time points, VEGF expression was significantly increased compared with the nonirradiated tissue. Similarly, X-rays down-regulated both HARP and iNOS expression 6 h after irradiation and the effect was reversed at later time points, similarly to the effect of X-rays on VEGF.
  
  
  CONCLUSIONS
  These data support the notion that X-rays increase the expression of genes that favor angiogenesis.
authors.affiliation: Laboratory of Molecular Pharmacology, Department of Pharmacy, School of Health Sciences, University of Patras, GR 26504, Greece.
authors.forename: C
authors.initials: C
authors.lastname: Polytarchou
authors.forename: T
authors.initials: T
authors.lastname: Gligoris
authors.forename: D
authors.initials: D
authors.lastname: Kardamakis
authors.forename: E
authors.initials: E
authors.lastname: Kotsaki
authors.forename: E
authors.initials: E
authors.lastname: Papadimitriou
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply / Q000528:radiation effects; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression / Q000528:radiation effects; D018919:Neovascularization, Physiologic / Q000235:genetics* / Q000528:radiation effects*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000235:genetics*; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics / Q000528:radiation effects; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics*; D014965:X-Rays
chemical_list: D002352:Carrier Proteins; D016207:Cytokines; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C066845:pleiotrophin; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II