IngentaConnect Enhancement of developmental capacity of meiotically inhibited bo...

Authors: P. Duque¹; C. Díez¹; L. Royo¹; P.L. Lorenzo²; G. Carneiro³; C.O. Hidalgo¹; N. Facal¹; E. Gómez¹

Source: Human Reproduction, Volume 17, Number 10, October 2002 , pp. 2706-2714(9)

Abstract:

BACKGROUND: Although high vitamin A may be teratogenic to the embryo, retinol has been shown to support oocyte developmental potential in vivo. Similarly, addition of retinol metabolite 9-cis-retinoic acid to in-vitro cultured oocytes could promote cytoplasmic maturation and subsequent early embryonic development. The objective of this study was to evaluate the effects of 5 nmol/l retinoic acid during in-vitro pre-maturation and maturation of bovine oocyte–cumulus complexes. METHODS AND RESULTS: Oocytes were aspirated from cows and either kept under meiotic arrest with 25

mol/l roscovitine and matured, or allowed to mature in permissive conditions (control). Cortical granule migration was analysed both after pre-maturation and maturation by fluorescent labelling of oocytes and subsequent laser confocal and fluorescence microscopy. Variables studied after in-vitro fertilization and culture in modified synthetic oviduct fluid were: (i) in-vitro embryonic development; (ii) ability of blastocysts to survive vitrification and warming; and (iii) differential cell counts measured by fluorescence microscopy. Although the presence of 5 nmol/l retinoic acid throughout in-vitro maturation was harmful, its presence during pre-maturation alone improved cytoplasmic granular migration, embryonic development, cryopreservation tolerance, total cell numbers and, as a consequence, embryonic quality. CONCLUSIONS: Pre-maturation in the presence of retinoic acid improves cytoplasmic competence of in-vitro matured bovine oocytes. Until more is known of the molecular mechanisms it would be irresponsible to use retinoic acid in maturation of human oocytes, especially in view of the narrow time window and possible species-specific differences in susceptibility and protection of the oocyte from epigenetic influences of retinol.

Keywords: bovine; in-vitro; oocyte; retinoic; roscovitine

Document Type: Research article

Affiliations: 1: SERIDA-CENSYRA, Camino de los Claveles, 604 Somió, 33203 Gijón, 2: Departamento de Fisiología Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040, Spain and 3: Department of Population Health and Reproduction, School of Veterinary Medicine, University of California Davis, CA 94616, USA

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Enhancement of developmental capacity of meiotically inhibited bovine oocytes by retinoic acid