title: Measuring oxidative stress: the confounding effect of lipid concentration in measures of lipid peroxidation.
abstract: Lipid peroxidation products are widely used as markers of oxidative damage in the organism. To properly interpret the information provided by these markers, it is necessary to know potential sources of bias and control confounding factors. Here, we investigated the relationship between two indicators of lipid mobilization (circulating levels of triglycerides and cholesterol) and two common markers of oxidative damage (plasma levels of malondialdehyde and hydroperoxides; the latter estimated from the d-ROMs assay kit). The following five avian species were studied: red-legged partridge (Alectoris rufa), zebra finch (Taeniopygia guttata), spotless starling (Sturnus unicolor), marsh harrier (Circus aeroginosus), and Montagu's harrier (Circus pygargus). In all cases, plasma triglyceride levels positively and significantly correlated with lipid peroxidation markers, explaining between 8% and 34% of their variability. Plasma cholesterol, in contrast, showed a significant positive relationship only among spotless starling nestlings and a marginally significant association in zebra finches. These results indicate that lipid peroxidation marker levels covary with circulating lipid levels. We discuss the potential causes and implications of this covariation and recommend that future studies that measure oxidative damage using lipid peroxidation markers report both raw and relative levels (i.e., corrected for circulating triglycerides). Whether the observed pattern also holds for other tissues and in other taxa would deserve further research.
authors: Department of Evolutionary Ecology, Estación Biológica de Doñana-Consejo Superior de Investigaciones Científicas (MNCN-CSIC), Avenida Americo Vespucio s/n, Isla de la Cartuja, 41092 Seville, Spain; 2Department of Evolutionary Ecology, Museo Nacional de Ciencias Naturales (MNCN-CSIC), José Gutiérrez Abascal, 2, 23005 Madrid, Spain; 3Instituto de Investigación en Recursos Cinegéticos (CSIC, Universidad de Castilla-La Mancha, Junta de Comunidades de Castilla-La Mancha), Ronda de Toledo s/n, 13071 Ciudad Real, Spain; 4Institut de Radioprotection et de Sûreté Nucléaire, Laboratoire d'Ecotoxicologie des Radionucléides (IRSN-LECO), Centre de Cadarache, 13115 St-Paul-Lez-Durance, France; 5Estación Experimental de Zonas Áridas (EEZA-CSIC), Carreterade Sacramento s/n, La Cañada de San Urbano, 04120 Almería, Spain.
authors: Lorenzo
authors: L
authors: Pérez-Rodríguez
authors: Ana A
authors: AA
authors: Romero-Haro
authors: Audrey
authors: A
authors: Sternalski
authors: Jaime
authors: J
authors: Muriel
authors: Francois
authors: F
authors: Mougeot
authors: Diego
authors: D
authors: Gil
authors: Carlos
authors: C
authors: Alonso-Alvarez
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood*; D001717:Birds / Q000097:blood*; D002784:Cholesterol / Q000097:blood; D015227:Lipid Peroxidation; D008054:Lipid Peroxides / Q000097:blood; D008315:Malondialdehyde / Q000097:blood; D018384:Oxidative Stress; D014280:Triglycerides / Q000097:blood
chemical_list: D015415:Biomarkers; D008054:Lipid Peroxides; D014280:Triglycerides; D008315:Malondialdehyde; D002784:Cholesterol