Embryotoxicity of the pesticide mirex in vitro.
Mirex is a pesticide that is environmentally stable, accumulates in body tissues, and is embryo- and feto-toxic at high concentrations in vivo. This study is the first to evaluate the effects of mirex on organogenesis-stage embryos in vitro. Mouse embryos were exposed on gestation day 8.5 for 24 h in whole-embryo culture to mirex at 100, 200, or 400 microg/ml dissolved in xylene and compared with xylene-treated controls (1, 2, or 4 microl/ml, respectively) and untreated controls. Embryos were evaluated for malformations, somite number, total protein content, and visceral yolk sac circulation. Potential embryotoxic mechanisms were evaluated by using PCNA stain for cell proliferation and the TUNEL assay for apoptotic cell death. Mirex-exposed embryos demonstrated increased malformation rates and decreased total embryonic protein contents at > or =200 microg/ml mirex, and decreased somite numbers and VYS circulation at > or =100 microg/ml mirex, compared with xylene-treated controls. There was no difference in PCNA levels or TUNEL staining in mirex-treated embryos compared with xylene-treated controls or untreated controls. Thus, mirex is embryotoxic in vitro to early organogenesis stage mouse embryos at concentrations > or =100 microg/ml, but the effects do not appear to be mediated by changes in cell proliferation or apoptotic cell death.
Department of Anatomy, Physiological Sciences, and Radiology, North Carolina State University, Raleigh, North Carolina, USA.
Ahmed A
AA
El-Bayomy
Ida W
IW
Smoak
Stacy
S
Branch
D000014:Abnormalities, Drug-Induced / Q000196:embryology / Q000209:etiology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000648:ultrastructure; D005314:Embryonic and Fetal Development / Q000187:drug effects; D005260:Female; D005326:Fetal Proteins / Q000096:biosynthesis; D005865:Gestational Age; D066298:In Vitro Techniques; D007306:Insecticides / Q000633:toxicity*; D051379:Mice; D008917:Mirex / Q000633:toxicity*; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D019170:Somites / Q000187:drug effects; D015017:Yolk Sac / Q000098:blood supply / Q000187:drug effects
D005326:Fetal Proteins; D007306:Insecticides; D018809:Proliferating Cell Nuclear Antigen; D008917:Mirex