title: Effects of multiple doses of ionizing radiation on cytokine expression in rat and human cells.
abstract: OBJECTIVE
  To determine the effect of daily fractionated irradiation on the expression of growth factors and cytokines in different cardiac and vascular cell types.
  
  
  METHODS
  Cell cultures of rat cardiac myocytes, fibroblasts, a rat cardiac microvascular endothelial cell line and human artery endothelial cells were irradiated with doses of 2 Gy, given daily during 5 consecutive days. Twenty-four hours after each fraction, gene expression was determined by competitive or semiquantitative polymerase chain reaction. Protein secretion into culture media was determined by enzyme-linked immunoabsorbant assay.
  
  
  RESULTS
  Of all investigated mRNA levels, transforming growth factor (TGF)-ss1 and fibroblast growth factor (FGF)-2 were slightly upregulated in the rat cardiac endothelial cell line after irradiation. TGF-ss1 protein secretion by these cells was slightly, but non-significantly, elevated. Interleukin 1ss protein levels in myocyte culture media were decreased in control cultures at days 3 and 4 compared with day 2. No significant changes were observed in expression of FGF-2 in either of the four cell types. Moreover, no changes were observed in gene expression of platelet-derived growth factors A, B and interleukin 8 in the human artery endothelial cells.
  
  
  CONCLUSIONS
  Fractionated irradiation leads to minor changes in the expression of specific cytokines in cardiac myocytes, fibroblasts and endothelial cells.
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, The Netherlands. m.boerma@lumc.nl
authors.forename: M
authors.initials: M
authors.lastname: Boerma
authors.forename: C I
authors.initials: CI
authors.lastname: Schutte-Bart
authors.forename: L E
authors.initials: LE
authors.lastname: Wedekind
authors.forename: H
authors.initials: H
authors.lastname: Beekhuizen
authors.forename: J
authors.initials: J
authors.lastname: Wondergem
mesh_terms: D000818:Animals; D002474:Cell-Free System; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis*; D018076:DNA, Complementary / Q000378:metabolism; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D042783:Endothelial Cells / Q000528:radiation effects; D004730:Endothelium, Vascular / Q000528:radiation effects*; D004797:Enzyme-Linked Immunosorbent Assay; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D032342:Muscle Cells / Q000528:radiation effects*; D010982:Platelet-Derived Growth Factor / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020574:Proto-Oncogene Proteins c-sis / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D011839:Radiation, Ionizing; D051381:Rats; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
chemical_list: D016207:Cytokines; D018076:DNA, Complementary; D016209:Interleukin-8; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C075278:platelet-derived growth factor A; D016222:Fibroblast Growth Factor 2