P–227 Fatty acid regulation of Nrf2/Keap1 pathway during mouse preimplantation embryo development
Notice bibliographique
Résumé
Abstract Study question Our objective is determining whether supplementing embryo culture media with palmitic acid and/or oleic acid impacts Nrf2/Keap1 antioxidant response pathways during preimplantation mouse embryo development. Summary answer Supplementation of embryo culture media with palmitic acid increases cellular Nrf2 levels per embryo after 48-hour culture, while oleic acid reverses this effect. What is known already Obese women experience higher incidence of infertility than women with healthy BMIs. The obese reproductive tract environment supporting preimplantation embryo development is likely to include enhanced free fatty acid (FFA) levels and increased accumulation of reactive oxygen species. Exposure to palmitic acid (PA) in vitro significantly impairs mouse embryo development while increasing ER stress mRNAs. Oleic acid (OA) reverses these effects. To further define effects of FFA exposure, we are characterizing the influence of FFAs on the Nrf2–Keap1 pathway and its downstream antioxidant defense systems. We hypothesize that PA treatment induces Nrf2-Keap1 activity, while OA treatment alleviates pathway activity. Study design, size, duration Female CD–1 mice (4–6 weeks) were super-ovulated via intraperitoneal injections of PMSG, followed 48 hours later by hCG. Female mice were mated with male CD–1 mice (6–8 months) overnight. Females were euthanized using CO2 and two-cell embryos were collected by flushing oviducts. Two-cell embryos were placed into KSOMaa-based treatment groups: 1) BSA (control); 2) 100µM PA; 3) 100µM OA; 4) 100µM PA+OA, and cultured for 48 hours (37 °C; 5% O2, 5% CO2, 90% N2). Participants/materials, setting, methods After 48-hour embryo culture, developmental stages of all mouse embryos were recorded. Immunofluorescence analysis of Nrf2 and Keap1 localization was performed for embryo treatments (BSA, 100µM PA, 100µM OA & 100µM PA+OA) using rabbit polyclonal anti-Nrf2 antibody, with Rhodamine-Phalloidin and DAPI staining. Embryos were imaged using confocal microscopy and Nrf2-positive cells were counted using ImageJ. Nrf2 and Keap1 mRNA abundances were assessed after culture in each treatment condition using RT-qPCR and the delta-delta Ct method. Main results and the role of chance Inclusion of 100µM PA in embryo culture significantly decreased blastocyst development frequency from 70.06±16.38% in the BSA (control) group to 11.61±8.19% in the PA-treated group (p < 0.0001). Embryo culture with 100µM OA and 100µM PA+OA co-treatment did not significantly impair blastocyst development (OA: 61.59±8.07%, p = 0.4053; PA+OA: 63.53±7.63%, p = 0.6204). Embryo culture with PA treatment significantly increased the mean percentage of Nrf2-positive cells to 56.83±30.49% compared with 21.22±15.63% in the control group (p < 0.0001). Conversely, 100µM OA and 100µM PA+OA treatments did not significantly affect Nrf2-positive cell frequencies compared with the control group (OA: 33.28±21.83%, p = 0.1825; PA+OA: 34.84±12.66%, p = 0.0691). Immunofluorescence results show that treating embryos with 100µM PA for 48 hours results in increased levels of cellular Nrf2, while combining 100µM PA with 100µM OA reversed these effects. Preliminary qPCR analysis showed no significant differences in Nrf2 or Keap1 relative transcript abundance between any embryo treatment groups. Nrf2 and Keap1 mRNA levels were both higher after embryo culture with 100µM OA than all other culture groups (p = 0.6268; p = 0.3201). Notably, Keap1 relative transcript levels dropped to undetectable levels after culture with 100µM PA, which suggests an increase in Nrf2 activation.Limitations, reasons for caution: While immunofluorescence localization of Nrf2/Keap1 provides insight into how the proteins behave during preimplantation embryo development, confocal images cannot determine protein-protein interactions or activity levels. Similarly, transcript information from RT-qPCR analysis only provides information about Nrf2 and Keap1 at the transcript level. Nrf2 activity will be assessed via downstream targets. Wider implications of the findings: The Nrf2–Keap1 pathway coordinates numerous cellular defence mechanisms, and is implicated in various diseases, including cancer. Establishing an impact of free fatty acid exposure on Nrf2–Keap1 during preimplantation embryo development will provide valuable information regarding the effects of maternal obesity on outcomes for embryos produced from these patients. Trial registration number Not applicable
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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 | 0,000 | 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) | 0,000 | 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 ».