135 <i>IN VITRO</i> DEVELOPMENT OF <i>IN VIVO</i> PRODUCED EMBRYOS FROZEN AT MORULA OR BLASTOCYST STAGES
Notice bibliographique
Résumé
This study was designed to compare cryotolerance between morulae and blastocysts collected from superovulated heifers. Twenty pubertal beef heifers (10 Nelore and 10 crossbred Nelore × Simmental) were superovulated with 100 mg of FSHp (Folltropin-V, Bioniche, Ontario, Canada), and embryos were collected and evaluated 7 days after estrus. Grades 1 and 2 embryos (IETS) were divided into four groups: morulae cryopreserved (MC) in liquid nitrogen ( n = 24); blastocysts cryopreserved (BC; n = 19); morulae fresh (MF; n = 23); and blastocysts fresh (BF; n = 18). For freezing, embryos were immersed in ethylene glycol (Ethylene Glycol Freeze Plus with 0.1 m sucrose, Bioniche, Pullman, WA, USA), and a standard protocol (cooling rate of –0.5°C/min) was used. Prior to in vitro culture, embryos were removed from nitrogen, kept at room temperature for 5 s, and put in a water bath at 30°C for 20 s. Within 5 h after recovery, thawed and fresh embryos were washed five times in holding solution (Holding Plus, Bioniche), transferred to synthetic oviduct fluid medium (SOF, Nutricell, Campinas, SP, Brazil), and cultured for 72 h. Embryos were evaluated at 48 and 72 h of culture. After the last evaluation, degenerate and non-hatched embryos were removed from culture, and the remaining embryos were measured by a graduated ocular coupled to the Motic Images Plus 2.0 program. Hatched blastocysts were kept in culture for an additional 48 h for post-hatching development assessment. For post-hatching culture PHD medium (Brandão DO et al . 2005 Biol. Reprod. 71, 2048–2055) was added into each well, to have a final composition of 50% SOF and 50% SOF PHD. At 120 h of culture (48 h of PHD culture) only morphologically normal blastocysts were measured. Comparison among groups was performed by ANOVA or chi-square test. Data are presented as mean ± SEM. After 48 h of culture, hatching rate (%) was significantly lower in cryopreserved (MC = 8.3 and BC = 21.5) than in fresh (MF = 56.5 and BF = 77.8) embryos ( P &lt; 0.05). However at 72 h, hatching rate was similar among BC (75.9), MF (78.3), and BF (88.9), being MC (41.7) still lower ( P &lt; 0.05). The diameter (µm) of hatched embryos after 72 h of culture was 272.8 ± 27.1a ( n = 8), 320.6 ± 18.6ab ( n = 14), 385.3 ± 14.2c ( n = 17), and 378.0 ± 22.0bc ( n = 16) for MC, BC, MF, and BF, respectively (a–c P &lt; 0.05). After 120 h of culture, the diameter of MC (379.0 ± 39.9; n = 8), although similar to BC (495.4 ± 59.6; n = 10), was smaller than MF (509.1 ± 36.5; n = 11) and BF (511.8 ± 41.2; n = 14). The results of this study with zebu cattle suggest that morulae are less resistant to cryopreservation in liquid nitrogen than blastocysts. Moreover, frozen/thawed embryos, when put in culture, present a slower development compared with fresh embryos. Financial support from CNPq and FAPESP from Brazil .
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 | 0,004 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| 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 ».