Equine Oocyte Competence for Nuclear and Cytoplasmic in Vitro Maturation: Effect of Follicle Size and Hormonal Environment1
| Autor: | J. Bezard, Eric Palmer, Guy Duchamp, Nadine Gérard, Ghylène Goudet |
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| Rok vydání: | 1997 |
| Předmět: |
endocrine system
medicine.medical_specialty urogenital system media_common.quotation_subject Cell Biology General Medicine Luteal phase Biology Oocyte Antral follicle In vitro maturation Andrology Follicle medicine.anatomical_structure Endocrinology Reproductive Medicine Internal medicine Follicular phase medicine Ovarian follicle Ovulation media_common |
| Zdroj: | Biology of Reproduction. 57:232-245 |
| ISSN: | 1529-7268 0006-3363 |
| DOI: | 10.1095/biolreprod57.2.232 |
| Popis: | Equine oocyte competence after in vitro maturation (IVM) was investigated in terms of the diameter of the follicle of origin and the stage of the estrous cycle, with three criteria of maturation: nuclear stage after DNA Hoechst staining, meiotic spindle morphology after tubulin immunocytochemical staining, and cortical granule localization after lectin labeling. Seven successive in vivo ultrasound-guided follicular punctures were performed on 10 cyclic saddle mares, alternatively at the end of the follicular phase (after induction of ovulation with a gonadotropin injection) and in midluteal phase (with or without a gonadotropin injection). Expanded cumulus-oocyte complexes (COCs) were stained at collection, and compact COCs were stained after in vitro culture. They were observed under a confocal microscope. Successive punctures on one mare provided 0.9 preovulatory COCs and 8 immature COCs per 22 days. Among the preovulatory oocytes, 55% had completed nuclear and cytoplasmic maturation, 86% of which displayed a normal meiotic spindle. Of the 262 oocytes cultured in vitro, 37% completed nuclear maturation. The nuclear and cytoplasmic maturation rate significantly increased with follicle diameter. The IVM rate tended to be higher in follicular phase and tended to increase in luteal phase with the gonadotropin injection. The meiotic spindle morphology was not significantly different between the classes of follicular diameters. This study provided the opportunity to increase the number of characterized oocytes collected per cycle and per mare. This is the first report showing the progressive acquisition of meiotic competence in the equine oocyte during antral follicle growth and is the only description of the equine meiotic spindle. |
| Databáze: | OpenAIRE |
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