241 STRATEGIES TO IMPROVE GLUTATHIONE CONTENT OF <i>IN VITRO</i> -MATURED BOVINE OOCYTES
Notice bibliographique
Résumé
Glutathione is the main non-enzymatic defense against oxidative stress and a critical part of oocyte maturation and normal fertilization. Our aim was to test different strategies to manipulate cellular glutathione (GSH) content of bovine in-vitro -matured (IVM) oocytes and study the development of embryos produced from such oocytes. The reducing agents lipoic acid (LA, intracellular) and dihydrolipoic acid (DHLA, extracellular) were compared to the cell-permeable reduced glutathione (GSH) donor glutathione ethyl ester (OET) for their effect on oocyte GSH content, oocyte maturation, and blastocyst development (OET only). Reagents were purchased from Sigma (St. Louis, MO, USA) unless stated otherwise. Cumulus–oocyte complexes (COCs) were aspirated from abattoir-derived ovaries and matured for 24 h in a humidified atmosphere of 6% CO2 at 38.5°C in modified tissue culture medium (mTCM199) supplemented with 2% (LA, DHLA) or 10% (OET) fetal calf serum (FCS; Gibco, Grand Island, NY, USA), 0.1 IU bLH and 0.1 IU bFSH (Sioux Biochemicals, Sioux City, IA, USA). COCs were matured in the presence of either LA (100 µm) or DHLA (100 µm) alone or in combination with L-cystine (CYS; 0.6 mm), CYS alone, or OET at 1, 3, and 5 mm. COCs matured under control and experimental conditions were denuded of cumulus cells (40 IU hyaluronidase) and scored for maturity. GSH content of MII oocytes was determined by colorimetric assay (Northwest Life Science Specialties, LLC, Vancouver, WA, USA). Oocytes matured in OET were inseminated with frozen/thawed bull sperm (2 × 106 mL-1), cultured to the blastocyst stage (COOK bovine medium, COOK Australia, Brisbane, Queensland, Australia), and subjected to differential cell count (propidium iodide/Hoechst). GSH levels (mean ± SEM) and developmental data (percentage) are expressed for n = 18–73 oocytes or embryos and were analyzed by ANOVA or chi-square test (significance, P = 0.05). LA alone failed to increase oocyte GSH content over 2% FCS control levels (6.98 ± 0.22 pmol/oocyte v . 5.26 ± 0.4 pmol/oocyte). DHLA alone significantly increased oocyte GSH content (9.64 ± 0.8 pmol/oocyte) compared to both LA and controls (10% FCS; 4.78 ± 0.36 pmol/oocyte). CYS alone (10.18 ± 0.58 pmol/oocyte) or in combination with LA (10.84 ± 0.37 pmol/oocyte) or DHLA (9.75 ± 0.66 pmol/oocyte) significantly increased GSH compared to controls. GSH content of MII oocytes matured in 5 mm OET (8.35 ± 0.35 pmol/oocyte) was significantly higher compared to control (5.07 ± 0.32 pmol/oocyte), 1 mm (4.21 ± 0.18 pmol/oocyte), and 3 mm (7.12 ± 0.35 pmol/oocyte) OET treatments. Maturation rates of oocytes were significantly reduced in 2% FCS (51.1–72%) compared to 10% FCS (90.5%). OET treatment (1–5 mm) did not significantly alter maturation rate compared to control (75–89.8%). Blastocyst development of IVM oocytes treated with 1 mm OET (22.5%) was significantly lower compared to 3 mm (42.3%) and 5 mm (41.1%) OET but not to control (33.6%). Blastocysts from IVM oocytes treated with 5 mm OET had significantly higher cell counts compared to controls (126 ± 6.4 cells v . 100.8 ± 5.2 cells). Bovine IVM is a valuable model for testing the efficacy of various strategies to increase oocyte cellular GSH. Both strategies improve oocyte GSH levels, and an increase in blastocyst cell number occurred with GSH donor treatment (5 mm OET).
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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) | 0,001 | 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 ».