SPERM DNA INTEGRITY AND CYTOSOLIC CALCIUM LEVELS ARE ASSOCIATED WITH THE IN VIVO FERTILITY OF BOVINE SEMEN
Notice bibliographique
Résumé
Cryopreserved bull sperm are less fertile than fresh due to sub-lethal damage that has not been fully characterized, although premature capacitation due to the freeze-thaw process may be partly responsible. Also, cryo-induced DNA damage would reduce the ability of the sperm to produce a viable embryo. Two experiments were therefore conducted on 14 bulls (1–4 semen batches/bull) classified into high- and low-fertility groups. In Experiment 1, we tested the hypothesis that sperm chromatin stability is related to bull fertility (as 56-day non-return rates) using the Sperm Chromatin Structure Assay (SCSA) on cryopreserved sperm at 0 and 7 h of incubation in conditions to mimic the female genital tract (Talp- BSA, 38.5°C, 5% CO2). In Experiment 2, we tested a second hypothesis, that the cytosolic calcium level of cryopreserved sperm is related to bull fertility using the fluorescent calcium indicator, indo-1, again at 0 and 7 h of incubation in physiological conditions. Additional functional sperm parameters, including motility (using CASA) and viability (using eosin – nigrosin) were assessed in Exp 1. In Exp 2, chlortetracycline fluorescence (CTC) patterns, sperm motility (CASA) and viability (measured by eosinnigrosin and propidium iodide (PI) during the evaluation of cytosolic calcium levels) were also assessed. The results of Exp 1 showed that the percentage of sperm with a high DNA fragmentation index (%DFI) was higher (P < .05) for bulls in the low fertility group immediately after thawing (0 h of incubation), indicating that DNA damage does reduce the fertilizing potential of the male. Moderate, significant correlations (ranging from −.54, P < .05, to −.74, P < .01) were obtained between %DFI and functional parameters, suggesting that DNA and functional damage are associated but do not necessarily occur concomitant with each other or are induced by the same stimuli. For Exp 2, internal calcium levels were negatively correlated with bull fertility after 7 h of incubation (P < .03), supporting previous reports that high calcium impairs sperm fertilizing capacity, possibly due to precocious capacitation or the onset of spontaneous acrosome reactions. In Exp 1, bull fertility correlated with total and progressive sperm motility (r = −.58 and r = −.55, P < .05, respectively) at 0 h, confirming their utility as a general predictor of fertilizing ability. Such correlation was not observed in Exp 2, however, this is likely because the sperm were centrifuged prior to calcium measures, but not before the SCSA. Cytosolic calcium correlated negatively with the percentages of motile sperm at 0 h (r = −.58, P < .05) and viable sperm (using PI) at 7 h of incubation (r = −.76, P < .01). Cytosolic calcium correlated positively with the percentages of CTC pattern B at 0 h (r = .67, P < .01) and negatively with pattern F at 7 h of incubation (r = −.53, P < .05). Together, these data indicate that relatively high cytosolic calcium levels occur in pattern B (capacitated) sperm, reflecting a common mechanism of compromised function in the context of cryopreserved semen used for artificial insemination. In conclusion, sperm DNA stability, cytosolic calcium levels, motility and viability are all related to fertility in vivo, and might serve as predictors of bull fertilizing capacity. (Thanks to L'Alliance Boviteq for supplying the semen and fertility data and to NSERC for financing. S I Peris was supported by the Egyptian government.) (poster)
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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 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 ».