title: Embryopathic effects of thalidomide and its hydrolysis products in rabbit embryo culture: evidence for a prostaglandin H synthase (PHS)-dependent, reactive oxygen species (ROS)-mediated mechanism.
abstract: Thalidomide (TD) causes birth defects in humans and rabbits via several potential mechanisms, including bioactivation by embryonic prostaglandin H synthase (PHS) enzymes to a reactive intermediate that enhances reactive oxygen species (ROS) formation. We show herein that TD in rabbit embryo culture produces relevant embryopathies, including decreases in head/brain development by 28% and limb bud growth by 71% (P<0.05). Two TD hydrolysis products, 2-phthalimidoglutaramic acid (PGMA) and 2-phthalimidoglutaric acid (PGA), were similarly embryopathic, attenuating otic vesicle (ear) and limb bud formation by up to 36 and 77%, respectively (P<0.05). TD, PGMA, and PGA all increased embryonic DNA oxidation measured as 8-oxoguanine (8-oxoG) by up to 2-fold (P<0.05). Co- or pretreatment with the PHS inhibitors eicosatetraynoic acid (ETYA) or acetylsalicylic acid (ASA), or the free-radical spin trap phenylbutylnitrone (PBN), completely blocked embryonic 8-oxoG formation and/or embryopathies initiated by TD, PGMA, and PGA. This is the first demonstration of limb bud embryopathies initiated by TD, as well as its hydrolysis products, in a mammalian embryo culture model of a species susceptible to TD in vivo, indicating that all likely contribute to TD teratogenicity in vivo, in part through PHS-dependent, ROS-mediated mechanisms.
authors.affiliation: Faculty of Pharmacy, University of Toronto, 144 College St., Toronto, ON, Canada.
authors.forename: Crystal J J
authors.initials: CJ
authors.lastname: Lee
authors.forename: Luisa L
authors.initials: LL
authors.lastname: Gonçalves
authors.forename: Peter G
authors.initials: PG
authors.lastname: Wells
mesh_terms: D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D001921:Brain / Q000002:abnormalities / Q000187:drug effects / Q000378:metabolism; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D004622:Embryo, Mammalian / Q000002:abnormalities / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D006868:Hydrolysis; D018878:Limb Buds / Q000002:abnormalities / Q000187:drug effects / Q000378:metabolism; D008297:Male; D015394:Molecular Structure; D010084:Oxidation-Reduction / Q000187:drug effects; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011817:Rabbits; D017382:Reactive Oxygen Species / Q000378:metabolism; D013723:Teratogens / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D013792:Thalidomide / Q000737:chemistry / Q000378:metabolism / Q000633:toxicity*; D046509:Tissue Culture Techniques
chemical_list: D017382:Reactive Oxygen Species; D013723:Teratogens; D015117:5,8,11,14-Eicosatetraynoic Acid; D013792:Thalidomide; D000080242:8-Hydroxy-2'-Deoxyguanosine; D011451:Prostaglandin-Endoperoxide Synthases; D003849:Deoxyguanosine; D001241:Aspirin