title: Developmental competence of equine oocytes: impacts of zona pellucida birefringence and maternally derived transcript expression.
abstract: In the present study, equine oocytes were classified into groups of presumably high and low developmental competence according to cumulus morphology, as well as oocyte ability to metabolise brilliant cresyl blue (BCB) stain. All oocytes were evaluated individually in terms of morphometry, zona pellucida birefringence (ZPB) and relative abundance of selected candidate genes. Oocytes with an expanded cumulus (Ex), representing those with presumably high developmental competence, had a significantly thicker zona (18.2 vs 17.3µm) and a significantly higher ZPB (64.6 vs 62.1) than oocytes with a compacted cumulus (Cp). Concurrently, oocytes classified as highly developmentally competent (BCB+) had a significantly thicker zona (18.8 vs 16.1µm) and significantly higher ZPB (63.1 vs 61.3) compared with oocytes classified as having low developmental competence. Expression of TFAM, STAT3 and CKS2 was significantly higher in Ex compared with Cp oocytes, whereas expression of COX1, ATPV6E and DNMT1 was lower. Together, the data reveal that developmentally competent equine oocytes are larger in size, have higher ZPB values and exhibit a typical genetic signature of maternally derived transcripts compared with oocytes with lower in vitro developmental competence.
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Abdollah
authors.initials: A
authors.lastname: Mohammadi-Sangcheshmeh
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Held
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Franca
authors.initials: F
authors.lastname: Rings
authors.affiliation: Animal Production Department, Faculty of Agriculture, Cairo University, 12613 Giza, Egypt.
authors.forename: Nasser
authors.initials: N
authors.lastname: Ghanem
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Dessie
authors.initials: D
authors.lastname: Salilew-Wondim
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Dawit
authors.initials: D
authors.lastname: Tesfaye
authors.affiliation: Clinic for Horses, Unit of Reproductive Medicine of Clinics, University of Veterinary Medicine Hannover Foundation, 30559 Hannover, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Sieme
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Karl
authors.initials: K
authors.lastname: Schellander
authors.affiliation: Institute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Hoelker
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001718:Birefringence; D042846:CDC2-CDC28 Kinases / Q000378:metabolism; D048429:Cell Size; D051545:Cyclooxygenase 1 / Q000378:metabolism; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D047108:Embryonic Development / Q000502:physiology*; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000502:physiology*; D006736:Horses / Q000502:physiology*; D009865:Oocytes / Q000166:cytology* / Q000502:physiology; D010078:Oxazines / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D014157:Transcription Factors / Q000378:metabolism; D015044:Zona Pellucida / Q000502:physiology*
chemical_list: D017931:DNA Primers; D010078:Oxazines; D050796:STAT3 Transcription Factor; D014157:Transcription Factors; C006797:Brilliant Cresyl Blue; D051545:Cyclooxygenase 1; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D042846:CDC2-CDC28 Kinases