title: Impaired secondary oxidant deactivation capacity and enhanced oxidative stress in serum from alveld affected lambs.
abstract: Alveld is a hepatogenous photosensitivity disorder in lambs. The aim of the study was to investigate if alveld affected lambs had a reduced capacity to handle oxidative stress induced from either endogenous and/or exogenous photosensitizers. Serum samples from alveld lambs (n=33) were compared to serum samples from control lambs (n=31) and exposed to a controlled amount of singlet oxygen ((1)O2). The sera from alveld lambs were found to have an impaired ability to deactivate reactive oxygen species (ROS) compared to control sera. A higher degree of initial hemolysis and a higher concentration of the exogenous photosensitizer phytoporphyrin (PP) were detected in alveld sera compared to the controls. The action spectrum for the formation of (1)O2 indicated that PP as well as the endogenous compound protoporphyrin IX (PP IX) may act as in vivo photosensitizers. A relatively high level of iron was detected in pooled serum from alveld lambs that showed a high degree of hemolysis. It was concluded that alveld photosensitivity is likely to be initiated by a photodynamic reaction involving PP and possibly also PP IX followed by a light-independent reaction involving hemoglobin-related products and catalysis by the Fenton reaction.
authors: School of Pharmacy, University of Oslo, P.O. Box 1068 Blindern, 0316 Oslo, Norway.
authors: Anne Bee
authors: AB
authors: Hegge
authors: Ivar
authors: I
authors: Mysterud
authors: Jan
authors: J
authors: Karlsen
authors: Olav M
authors: OM
authors: Skulberg
authors: Carl M M
authors: CM
authors: Laane
authors: Trond
authors: T
authors: Schumacher
authors: Hanne Hjorth
authors: HH
authors: Tønnesen
mesh_terms: D000818:Animals; D006461:Hemolysis; D008903:Minerals / Q000378:metabolism; D016877:Oxidants / Q000097:blood* / Q000378:metabolism*; D018384:Oxidative Stress; D010787:Photosensitivity Disorders / Q000097:blood / Q000276:immunology / Q000378:metabolism / Q000662:veterinary*; D011524:Protoporphyrins / Q000378:metabolism; D012756:Sheep; D012757:Sheep Diseases / Q000097:blood* / Q000276:immunology / Q000378:metabolism*; D026082:Singlet Oxygen / Q000378:metabolism
chemical_list: D008903:Minerals; D016877:Oxidants; D011524:Protoporphyrins; D026082:Singlet Oxygen; C028025:protoporphyrin IX
keywords: Alveld; Blood serum; Hemolysis; Oxidative stress; Reactive oxygen species; Secondary oxidant deactivation