title: Meiotic progression, mitochondrial features and fertilisation characteristics of porcine oocytes with different G6PDH activities.
abstract: The aim of the present study was to investigate the developmental competence, mitochondrial characteristics and chromatin status of immature follicular porcine oocytes selected for their glucose-6-phosphate dehydrogenase (G6PDH) activity by brilliant cresyl blue (BCB) staining. In Experiment 1, the oocyte parameters were determined in parallel right after BCB staining (T(0)), after 22 h of in vitro maturation (IVM) (T(22)) and after 44 h of IVM (T(44)) (n = 496). BCB-stained oocytes (BCB+) at T(0) were characterised by fibrillated chromatin filaments in their germinal vesicles (GV) and diakinesis stages whereas unstained (BCB-) oocytes at T(0) contained in their GV mainly condensed stages of chromatin (P < 0.05). After 22 h of IVM BCB+ oocytes showed a prominent chromatin configuration of metaphase I and after 44 h the majority developed a M II nuclear configuration in contrast to the BCB- group (P < 0.0001). Differences were also observed between the two oocyte populations in their mitochondrial activity (P < 0.05). At the beginning of IVM BCB+ oocytes were characterised by high mitochondrial activity in their cytoplasm. The BCB+ oocytes showed clear visible homogenous distributions of mitochondria (P < 0.005) and contained more aggregated clusters of mitochondria in contrast to BCB- oocytes (P < 0.005). In Experiment 2, 318 oocytes were tested for their G6PDH activity and introduced to IVM and IVF. Only oocytes from the BCB+ group, which were matured after 44 h up to the stage of M II (81.6%) were fertilised (17.4%), penetrated (46%) or activated (15.6%) after IVF. These results indicate a relationship between the G6PDH activity of porcine oocytes before IVM and their subsequent nuclear development, mitochondrial activity and aggregation.
authors.affiliation: Research Institute for Animal Breeding and Nutrition, Research Group of Reproductive Biology, 2053 Herceghalom, Hungary.
authors.forename: István
authors.initials: I
authors.lastname: Egerszegi
authors.forename: Hannelore
authors.initials: H
authors.lastname: Alm
authors.forename: József
authors.initials: J
authors.lastname: Rátky
authors.forename: Bassiouni
authors.initials: B
authors.lastname: Heleil
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Brüssow
authors.forename: Helmut
authors.initials: H
authors.lastname: Torner
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000502:physiology; D002843:Chromatin / Q000648:ultrastructure; D004396:Coloring Agents; D003593:Cytoplasm / Q000648:ultrastructure; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism*; D008540:Meiosis; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000502:physiology / Q000648:ultrastructure*; D009865:Oocytes / Q000201:enzymology / Q000502:physiology* / Q000648:ultrastructure; D010078:Oxazines; D013552:Swine
chemical_list: D002843:Chromatin; D004396:Coloring Agents; D010078:Oxazines; C006797:Brilliant Cresyl Blue; D005954:Glucosephosphate Dehydrogenase