58 Reduced nutrient availability during in vitro culture improves embryo production and morphological quality and alters metabolic status of bovine embryos
Notice bibliographique
Résumé
In vitro production (IVP) of embryos is designed to reproduce an environment that resembles the female reproductive tract. However, the system does not perform optimally in terms of quality and embryo production. A major setback lies in the loss of dynamics observed in a static in vitro system, which might affect the availability of substrates that reach the embryo. A reduction in the amount of nutrients in media has been used as an approach to improve IVP (Ermisch et al. 2020 Sci. Rep. 10, 9263; https://doi.org/10.1038/s41598-020-66019-4). The present study aimed at describing a defined sequential medium (embryonic culture supplementation, ECS) and to investigate the effect of reducing nutrient availability on embryo production, quality, and metabolism. ECS was developed in our laboratory and is a serum-free, salt-based culture medium supplemented with the amount of energy substrates and amino acids found in bovine oviduct (Ov) and uterus (Ut) fluids as previously described (Hugentobler et al. 2007 Mol. Reprod. Dev. 74, 445–454; https://doi.org/10.1002/mrd.20607; Hugentobler et al. 2008 Mol. Reprod. Dev. 75, 496–503; https://doi.org/10.1002/mrd.20760). Embryos were cultured according to the following ECS supplementation: ECS100 (supplemented with 8 mg mL−1 bovine serum albumin and 100% of the energy substrates and amino acids concentrations of the Ov and Ut fluids) and ECS50 (half dilution of ECS100). Bovine oocytes from abattoir ovaries were submitted to IVP using standard protocols. On Day 0 of in vitro culture, presumptive zygotes were randomly divided into groups ECS100-Ov or ECS50-Ov. On Day 4, embryos were respectively transferred to ECS100-Ut and ECS50-Ut. Expanded blastocysts were collected on Day 7 to assess embryo production, morphology (total cell number by Hoescht 33342 staining; inner cell mass and trophectoderm cells by CDX2 immunostaining), and metabolic status (mitochondrial activity and reactive oxygen species content by MitotrackerTM RedCMXRos and CellROXTM Green staining, ThermoFisher Scientific; NADH and FAD+ by autofluorescence). Data were analysed by Student’s t-test (a = 4%). Although cleavage rates were similar between ECS50 and ECS100 (78.13 ± 3.73 vs. 79.70 ± 4.18; P = 0.788), blastocyst rates were positively influenced by the reduction in concentration (28.88 ± 1.74 vs. 16.73 ± 2.41; P = 0.004). This difference likely comes from a blockage at the morula stage in group ECS100, because the conversion from morula to blastocyst was 20% lower in this group (57.73 ± 3.81 vs. 38.15 ± 3.45; P = 0.008). In terms of morphology, blastocysts produced in ECS50 had a higher number of cells (152.4 ± 9.61 vs. 118.3 ± 7.22; P = 0.036), which is explained by the higher number of trophectoderm cells. Finally, metabolic status was affected by nutrient reduction: embryos from ECS50 had higher mitochondrial activity, reactive oxygen species content (P < 0.0001), and lower NADH (P = 0.01), suggesting higher oxidative phosphorylation to produce energy, as expected at this stage. In conclusion, ECS is a functional medium, and a reduced nutrient concentration (ECS50) improves embryo production, morphological quality, and metabolic status of blastocysts, suggesting that culture conditions must be adapted to the in vitro system rather than resembling in vivo conditions. This research was funded by FAPESP (2016/00350-0, 2017/18384-0).
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 distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,003 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| 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) | 0,000 | 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 tête enseignante, 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 ».