title: Differential cytotoxic effects of mono-(2-ethylhexyl) phthalate on blastomere-derived embryonic stem cells and differentiating neurons.
abstract: Potential applications of embryonic stem (ES) cells are not limited to regenerative medicine but can also include in vitro screening of various toxicants. In this study, we established mouse ES cell lines from isolated blastomeres of two-cell stage embryos and examined their potential use as an in vitro system for the study of developmental toxicity. Two ES cell lines were established from 69 blastomere-derived blastocysts (2.9%). The blastomere-derived ES (bm-ES) cells were treated with mono-(2-ethylhexyl) phthalate (MEHP) in an undifferentiated state or after directed differentiation into early neural cell types. We observed significantly decreased cell viability when undifferentiated bm-ES cells were exposed to a high dose of MEHP (1000 microM). The cytotoxic effects of MEHP were accompanied by increased DNA fragmentation, nuclear condensation, and activation of Caspase-3, which are biochemical and morphological features of apoptosis. Compared to undifferentiated bm-ES cells, considerably lower doses of MEHP (50 and 100 microM) were sufficient to induce cell death in early neurons differentiated from bm-ES cells. At the lower doses, the number of neural cells positive for the active form of Caspase-3 was greater than that for undifferentiated bm-ES cells. Thus, our data indicate that differentiating neurons are more sensitive to MEHP than undifferentiated ES cells, and that undifferentiated ES cells may have more efficient defense systems against cytotoxic stresses. These findings might contribute to the development of a new predictive screening method for assessment of hazards for developmental toxicity.
authors.affiliation: Laboratory of Reproductive Endocrinology, Department of Life Science, College of Natural Sciences, Hanyang University, Seongdong-Gu, Seoul, Republic of Korea. seungzzang@paran.com
authors.forename: Chun Kyu
authors.initials: CK
authors.lastname: Lim
authors.forename: Suel-Kee
authors.initials: SK
authors.lastname: Kim
authors.forename: Duck Sung
authors.initials: DS
authors.lastname: Ko
authors.forename: Jea Won
authors.initials: JW
authors.lastname: Cho
authors.forename: Jin Hyun
authors.initials: JH
authors.lastname: Jun
authors.forename: Su-Yeon
authors.initials: SY
authors.lastname: An
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Han
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Yong-Dal
authors.initials: YD
authors.lastname: Yoon
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001757:Blastomeres / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D053148:Caspase 3 / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004789:Enzyme Activation; D051379:Mice; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D010968:Plasticizers / Q000633:toxicity*; D018570:Risk Assessment; D013997:Time Factors; D018675:Toxicity Tests
chemical_list: D010968:Plasticizers; D004051:Diethylhexyl Phthalate; C505409:Casp3 protein, mouse; D053148:Caspase 3; C016599:mono-(2-ethylhexyl)phthalate