title: Cytoplasmic movement profiles of mouse surrounding nucleolus and not-surrounding nucleolus antral oocytes during meiotic resumption.
abstract: Full-grown mouse antral oocytes are classified as surrounding nucleolus (SN) or not-surrounding nucleolus (NSN), depending on the respective presence or absence of a ring of Hoechst-positive chromatin surrounding the nucleolus. In culture, both types of oocytes resume meiosis and reach the metaphase II (MII) stage, but following insemination, NSN oocytes arrest at the two-cell stage whereas SN oocytes may develop to term. By coupling time-lapse bright-field microscopy with image analysis based on particle image velocimetry, we provide the first systematic measure of the changes to the cytoplasmic movement velocity (CMV) occurring during the germinal vesicle-to-MII (GV-to-MII) transition of these two types of oocytes. Compared to SN oocytes, NSN oocytes display a delayed GV-to-MII transition, which can be mostly explained by retarded germinal vesicle break down and first polar body extrusion. SN and NSN oocytes also exhibit significantly different CMV profiles at four main time-lapse intervals, although this difference was not predictive of SN or NSN oocyte origin because of the high variability in CMV. When CMV profile was analyzed through a trained artificial neural network, however, each single SN or NSN oocyte was blindly identified with a probability of 92.2% and 88.7%, respectively. Thus, the CMV profile recorded during meiotic resumption may be exploited as a cytological signature for the non-invasive assessment of the oocyte developmental potential, and could be informative for the analysis of the GV-to-MII transition of oocytes of other species.
authors.affiliation: Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Thi Thu Hien
authors.initials: TTH
authors.lastname: Bui
authors.affiliation: Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Belli
authors.affiliation: Dipartimento di Ingegneria Industriale e dell'Informazione, University of Pavia, Pavia, Italy.|Centre for Health Technologies (C.H.T.), University of Pavia, Pavia, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Fassina
authors.affiliation: Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Vigone
authors.affiliation: Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Merico
authors.affiliation: Laboratorio di Biologia dello Sviluppo, Dipartimento di Biologia e Biotecnologie "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.|Centre for Health Technologies (C.H.T.), University of Pavia, Pavia, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Garagna
authors.affiliation: Dipartimento di Medicina e Chirurgia, University of Parma, Parma, Italy.
authors.forename: Maurizio
authors.identifier: 0000-0002-6221-6726
authors.initials: M
authors.lastname: Zuccotti
mesh_terms: D000818:Animals; D002466:Cell Nucleolus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005260:Female; D008540:Meiosis / Q000502:physiology*; D051379:Mice; D009865:Oocytes / Q000378:metabolism*
keywords: cytoplasmic movement; feedforward artificial neural network; oocyte developmental competence; particle image velocimetry; time-lapse