Faculty of Pharmacy, University of Toronto, 144 College St., Toronto, ON, Canada.
FASEB J. 2011 Jul;25(7):2468-83. doi: 10.1096/fj.10-178814. Epub 2011 Apr 18.
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.
沙利度胺（TD）通过几种潜在机制在人类和兔子中引起出生缺陷，包括通过胚胎前列腺素 H 合酶（PHS）酶生物激活为增强活性氧（ROS）形成的反应性中间产物。我们在此表明，TD 在兔胚胎培养中产生相关的胚胎病，包括头部/大脑发育减少 28%和肢芽生长减少 71%（P<0.05）。TD 的两种水解产物 2-邻苯二甲酰亚氨基戊二酸（PGMA）和 2-邻苯二甲酰亚氨基戊二酸（PGA）也具有类似的胚胎病，分别使耳泡（耳朵）和肢芽形成减少高达 36%和 77%（P<0.05）。TD、PGMA 和 PGA 均使胚胎 DNA 氧化增加，测量为 8-氧鸟嘌呤（8-oxoG）增加高达 2 倍（P<0.05）。PHS 抑制剂二十碳四烯酸（ETYA）或乙酰水杨酸（ASA）或自由基捕获剂苯丁基硝酮（PBN）的共处理或预处理完全阻断了 TD、PGMA 和 PGA 引发的胚胎 8-oxoG 形成和/或胚胎病。这是在易受 TD 体内影响的哺乳动物胚胎培养模型中首次证明 TD 及其水解产物引发肢芽胚胎病，表明所有这些都可能通过 PHS 依赖性 ROS 介导的机制部分导致 TD 的致畸性。
