89 IMPROVED POST-WARMING DEVELOPMENTAL COMPETENCE OF OPEN PULLED STRAW-VITRIFIED <i>IN VITRO</i> -PRODUCED BOVINE BLASTOCYSTS BY SUBLETHAL HYDROSTATIC PRESSURE PRETREATMENT
Notice bibliographique
Résumé
Vitrification of in vitro (IVP)-produced bovine blastocysts is well established, reaching post-warming hatching rates close to 70–80% in vitro . Nevertheless, improvements still are needed regarding realizable pregnancy rates. High hydrostatic pressure (HHP) treatment of fresh boar semen before freezing increased the litter size achieved by insemination of frozen–thawed boar semen (Kuo et al . 2007 6th Int. Conf. Boar Semen Pres, Alliston, ON, Canada, poster #22); HHP treatment-related improvements were also observed in the in vitro cryosurvival of mouse blastocysts (Pribenszky et al . 2004 Reprod. Fertil. Dev. 17, 199–200), bull and boar semen, and pig oocytes, theoretically by the sublethal stress-induced production/stabilization of shock proteins (Pribenszky et al . 2006 Reprod. Fertil. Dev. 18, 162–163; 2007 Reprod. Fertil. Dev. 19, 181–182; and b; Du et al . 2007). The aim of the present study was to improve the post-warming in vitro developmental competence of vitrified bovine IVP blastocysts through the application of HHP as pre-treatment, in order to apply the protocol in later in vivo experiments. Day 7 IVP blastocysts were aspirated in TQC holding medium (AB Technology, Sao Paulo, Brazil) into 0.25-mL straws. Straws were pressure-treated in a custom-made hydrostatic pressure chamber (Cryo-Innovation Ltd., Budapest, Hungary), using water as pressure medium. Six hundred bar pressure was applied for 60 min at 32°C. Immediately after pressure treatment, or following 60- or 120-min incubation, embryos were vitrified and warmed using open pulled straws (OPS) according to the method of Vajta et al . (1998 Mol. Reprod. Dev. 51, 53–58). Untreated blastocysts were vitrified as controls. After warming, embryos were cultured in vitro in SOF (Holm et al . 1999 Theriogenology 52, 683–700) for 72 h. Embryos were checked for re-expansion and hatching at 4, 24, 48, and 72 h post-warming. For the experiment, 404 blastocysts were used in 5 replicates. Logistic regression was used for statistical evaluation. All vitrified groups were inferior compared to the non-vitrified control (97%, 97%, 98, and 100% expansion; 0%, 23%, 72 and 91% hatching at 4, 24, 48, and 72 h, respectively). HHP treatment had a significant effect ( P > 0.05) on the post-warming developmental competence of vitrified blastocysts. HHP treatment followed by 60 min of equilibration proved to be superior among all treatment groups regarding both re-expansion and hatching rates and the speed of resumption of normal in vitro development (HHP treatment followed by a 60-min equilibration time before vitrification/warming: re-expansion rates: 88%, 89%, 85, and 90%; hatching rates: 0%, 22%, 51, and 73% v . non-treated vitrified/warmed controls: re-expansion rates: 63%, 69%, 71, and 81%; hatching rates: 0%, 6%, 43, and 63%; at 4, 24, 48, and 72 h post-warm, respectively). In conclusion, hydrostatic pressure pre-treatment significantly improved in vitro survival and hatching rates as well as the speed of resumption of normal in vitro development. Further studies are needed to reveal the molecular-biological implications of the HHP treatments, as well as field trials to test if the in vitro improvements can be confirmed by pregnancy and birth rates. This work was supported by EMBRAPA and a Kozma grant, Hungary .
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».