title: Comparative pathogenesis of haloacetic acid and protein kinase inhibitor embryotoxicity in mouse whole embryo culture.
abstract: Haloacetic acids (HAs) are embryotoxic contaminants commonly found in drinking water. The mechanism of HA embryotoxicity has not been defined, but may be mediated in part by protein kinase C (PKC) inhibition. This study was conducted to evaluate the pathogenesis of HA embryotoxicity, and to compare these data with those from specific (Bis I) and non-specific (staurosporine) inhibitors of PKC. Embryos were incubated for varying times with several HAs, Bis I, staurosporine, or Bis V (a negative control). Cell cycle analysis was performed by flow cytometry following nuclear staining with propidium iodide; apoptosis was evaluated by fluorescence microscopy following LysoTracker staining. At concentrations producing 100% embryotoxicity with no embryolethality, only staurosporine perturbed the cell cycle. However, flow cytometry revealed accumulation of sub-G1 events (an apoptotic indicator) across time with bromochloroacetic acid, dichloroacetic acid, and staurosporine, but not dibromoacetic acid, Bis I, or Bis V. Sub-G1 events were particularly prominent in the head region, and remained at control levels in the heart. LysoTracker staining confirmed a similar pattern of apoptosis in the intact embryo; BCA and DCA produced intense staining in the prosencephalon, with virtually no staining in the heart. These data indicate that while cell-cycle perturbation may not mediate the pathogenesis of HA embryotoxicity, these agents do induce embryonic apoptosis. In addition, the lack of Bis I-induced apoptosis indicates that PKC inhibition is unlikely to be the sole mediator of HA embryotoxicity.
authors.affiliation: Curriculum in Toxicology, University of North Carolina at Chapel Hill, 27599-7270, USA.
authors.forename: K W
authors.initials: KW
authors.lastname: Ward
authors.forename: E H
authors.initials: EH
authors.lastname: Rogers
authors.forename: E S
authors.initials: ES
authors.lastname: Hunter
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D046508:Culture Techniques; D005314:Embryonic and Fetal Development / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000633:toxicity*; D005260:Female; D005434:Flow Cytometry; D007211:Indoles / Q000633:toxicity*; D008297:Male; D008301:Maleimides / Q000633:toxicity*; D051379:Mice; D011247:Pregnancy; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D019311:Staurosporine / Q000633:toxicity*
chemical_list: D004791:Enzyme Inhibitors; D007211:Indoles; D008301:Maleimides; C115989:bisindolylmaleimide V; D011493:Protein Kinase C; D019311:Staurosporine; C070515:bisindolylmaleimide I