title: Markers of lipid peroxidation and α-tocopherol levels in the blood and neoplastic tissue of dogs with malignant mammary gland tumors.
abstract: BACKGROUND
  Excess reactive oxygen species due to oxidative stress and the ensuing lipid peroxidation are believed to be involved in mammary gland tumor (MGT) pathogenesis.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the extent of lipid peroxidation as evidenced by thiobarbituric acid-reactive substances (TBARS) formation, and the concentration of α-tocopherol as an inhibitor of lipid peroxidation, in blood and neoplastic tissue of dogs with malignant MGT. The correlation between inflammatory cell infiltration score and TBARS or α-tocopherol in MGT was also evaluated.
  
  
  METHODS
  Sixteen intact female dogs with malignant MGT and 12 clinically healthy and age/weight-matched controls were included in the study. In all dogs, serum TBARS, α-tocopherol, total cholesterol, and triglycerides were measured. Tissue TBARS and α-tocopherol levels were determined in 1 cm(3) sized tissue samples collected from MGT and adjacent, ipsilateral, normal mammary gland tissue from the 16 affected dogs. The degree of inflammatory cell tumor infiltration was evaluated histologically.
  
  
  RESULTS
  There were no statistically significant differences in serum levels of TBARS, α-tocopherol, total cholesterol, and triglycerides between dogs with and without malignant MGT. TBARS were significantly higher, whereas α-tocopherol was lower in neoplastic tissue when compared with normal mammary gland tissue. There was no correlation between TBARS or α-tocopherol concentration and the inflammatory cell infiltration score in neoplastic tissue.
  
  
  CONCLUSIONS
  The increased level of TBARS suggests oxidative stress induction in canine malignant MGT. The origin of this phenomenon is not clear, as a potential oxidative burst could not be attributed to inflammatory cells infiltrating the tumors.
authors.affiliation: Department of Clinical Studies - Companion Animal Clinic, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Karayannopoulou
authors.forename: Anna
authors.initials: A
authors.lastname: Fytianou
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Assaloumidis
authors.forename: Dimitra
authors.initials: D
authors.lastname: Psalla
authors.forename: Theodoros C
authors.initials: TC
authors.lastname: Constantinidis
authors.forename: Eleni
authors.initials: E
authors.lastname: Kaldrymidou
authors.forename: Alexander F
authors.initials: AF
authors.lastname: Koutinas
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D004283:Dog Diseases / Q000378:metabolism / Q000473:pathology*; D004285:Dogs; D005260:Female; D015227:Lipid Peroxidation; D008321:Mammary Glands, Animal / Q000378:metabolism; D015674:Mammary Neoplasms, Animal / Q000378:metabolism / Q000473:pathology*; D018384:Oxidative Stress; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D024502:alpha-Tocopherol / Q000097:blood* / Q000378:metabolism
chemical_list: D015415:Biomarkers; D017392:Thiobarbituric Acid Reactive Substances; D024502:alpha-Tocopherol
keywords: Inflammatory cancer; oxidative burst; thiobarbituric acid-reactive substances