title: The production and composition of rat sebum is unaffected by 3 Gy gamma radiation.
abstract: OBJECTIVE
  The aim of this work was to use metabolomics to evaluate sebum as a source of biomarkers for gamma-radiation exposure in the rat, and potentially in man. Proof of concept of radiation metabolomics was previously demonstrated in both mouse and rat urine, from the radiation dose- and time-dependent excretion of a set of urinary biomarkers.
  
  
  METHODS
  Rats were gamma-irradiated (3 Gy) or sham irradiated and groups of rats were euthanised at 1 h or 24 h post-irradiation. Sebum was collected by multiple washings of the carcasses with acetone. Nonpolar lipids were extracted, methylated, separated and quantitated using gas chromatography-mass spectrometry (GCMS). Metabolomic analysis of the GCMS data was performed using both orthogonal projection to latent structures-discriminant analysis and random forests machine learning algorithm.
  
  
  RESULTS
  Irradiation did not alter sebum production. A total of 35 lipids were identified in rat sebum, 29 fatty acids, five fatty aldehydes, and cholesterol. Metabolomics showed that three fatty acids, palmitic, 2-hydroxypalmitic, and stearic acids were potential biomarkers. Sebaceous palmitic acid was marginally statistically significantly elevated (7.5-8.4%) at 24 h post-irradiation.
  
  
  CONCLUSIONS
  Rat sebaceous gland appears refractory to 3 Gy gamma-irradiation. Unfortunately, collection of sebum shortly after gamma-irradiation is unlikely to form the basis of high-throughput non-invasive radiation biodosimetry in man.
authors.affiliation: Institute of Clinical Pharmacology and Visceral Research, University of Bern, Bern, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Lanz
authors.forename: Monika
authors.initials: M
authors.lastname: Ledermann
authors.forename: Josef
authors.initials: J
authors.lastname: Slavík
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Idle
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D015415:Biomarkers / Q000032:analysis; D001822:Body Burden; D005720:Gamma Rays; D008297:Male; D051379:Mice; D011829:Radiation Dosage; D051381:Rats; D011916:Rats, Inbred F344; D012627:Sebaceous Glands / Q000378:metabolism* / Q000528:radiation effects*; D012629:Sebum / Q000737:chemistry*; D014915:Whole-Body Counting / Q000379:methods*; D014916:Whole-Body Irradiation
chemical_list: D015415:Biomarkers