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CARBENDAZIM (MBC) DISRUPTS OOCYTE SPINDLE FUNCTION AND INDUCES ANEUPLOIDY IN HAMSTERS EXPOSED DURING FERTILIZATION (MEIOSIS II)
Citation:
Zuelke, K. AND S. Perreault. CARBENDAZIM (MBC) DISRUPTS OOCYTE SPINDLE FUNCTION AND INDUCES ANEUPLOIDY IN HAMSTERS EXPOSED DURING FERTILIZATION (MEIOSIS II). U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/515.
Description:
Peri-fertilization exposure to Carbendazim (MBC; a microtubule poison) induces infertility and early pregnancy loss (EPL) in hamsters. resently, both in vivo and in vitro techniques were employed to characterize the effects of MBC on cellular aspects of fertilization in hamsters. xposure to MBC during either in vivo or in vitro fertilization (IVF) induced identical morphological abnormalities in the maternal chromatin of zygotes and embryos which were characteristic of spindle disruption. hese abnormalities included either multiple second polar bodies (PB2), and/or multiple small female pronuclei (PN), or meiotic arrest. ultiple PB,, multiple female PN, multiple PB2 with multiple female PN, or meiotic arrest were exhibited by approximately 31%, 15%, 12%, or 2% of the in vivo zygotes; and 3%, 16%, 36%, or 20% of IVF zygotes, respectively. dverse effects of MBC persisted to day 2 of pregnancy as indicated by decreased (p < 0.05) embryo development to the 2-cell stage and the presence of micronuclei in 6% of 2-cell embryos from MBC-treated females. mmofluorescence analysis of microtubules (MT's) confirmed that MBC disrupted spindle MT's during IVF. umerical chromosome analysis revealed that a single dose of MBC administered during in vivo fertilization induced aneuploidy in the resulting pronuclear-stage zygotes. he present data point to two mechanisms by which peri-fertilization MBC exposure may induce EPL: 1) arrested meiosis with no zygotic cleavage; or 2) induction of zygotic aneuploidy with subsequent developmental arrest.