title: Effect of nicotine on in vitro maturation of bovine oocytes.
abstract: The putative effect of nicotine on maturation and the chromosomal complement of bovine oocytes were investigated in the present study. Cumulus-enclosed oocytes were incubated in maturation medium with 0, 0.5, 1.0, 2.5, 5.0, and 10.0 mmol concentrations of nicotine. The results indicated that: (1) nicotine affected cumulus cell expansion in a dose-dependent manner and the perivitelline space failed to form when concentrations were equal to or greater than 5.0 mmol; (2) oocytes treated with 0.5 and 1.0 mmol nicotine concentrations resulted in maturation rates (83.3% and 85.9%, respectively) which was similar to the control (86.2%), whereas treatment with 2.5 and 5.0 mmol concentrations significantly decreased maturation rates to 70.2% and 26.7%, respectively; (3) nicotine at or over 2.5 mmol caused extremely irregular meiotic spindles and interrupted microfilament organization; (4) chromosomal analyses of oocytes with PB1 showed that oocytes derived from 0.5 and 1.0 mmol nicotine groups had haploid complements similar to the control (87-90%), but when the concentrations were increased to 2.5 and 5.0 mmol the haploid state was significantly reduced to around 70%; (5) oocytes at GVBD (germinal vesicle breakdown) and metaphase I stages were less affected by nicotine at 5.0 and 10.0 mmol concentrations than GV-stage oocytes; (6) maturation rates of the short-term nicotine-treated oocytes could be improved when subsequently incubated in normal maturation medium. Prolonged culture of nicotine-pretreated oocytes resulted in self-activation and some oocytes formed 1 or 2 pronuclei. In conclusion, nicotine affects bovine oocyte cumulus cell expansion, maturation rate, and chromosomal complement in a dose-dependent and an oocyte-stage-dependent manner.
authors.affiliation: Department of Animal, Dairy and Veterinary Sciences, and Center for Integrated Biosystems, Utah State University, Logan, UT 84321, United States.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liu
authors.forename: Guang-Peng
authors.initials: GP
authors.lastname: Li
authors.forename: Lee F
authors.initials: LF
authors.lastname: Rickords
authors.forename: Kenneth L
authors.initials: KL
authors.lastname: White
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Sessions
authors.forename: Kenneth I
authors.initials: KI
authors.lastname: Aston
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Bunch
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002869:Chromosome Aberrations / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D005260:Female; D006238:Haploidy; D008540:Meiosis / Q000187:drug effects; D008856:Microscopy, Fluorescence / Q000662:veterinary*; D008870:Microtubules / Q000187:drug effects; D009538:Nicotine / Q000494:pharmacology*; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D009538:Nicotine