Suppression of Mitochondrial Activity in Activated Bovine Sperm Advances Capacitation Status and Induces Normal Embryogenesis.
Notice bibliographique
Résumé
We have previously shown that activated bovine sperm induce capacitation. Activated sperm can fertilize normally. However, our previous study also indicated that the selection and injection (ICSI) of activated and hyperactivated sperm into bovine oocytes induced chromosomal aberration during early stages of development. Activation of sperm motility is a highly energetic process. Mitochondria produce significant amounts of ATP and reactive oxygen species (ROS) in those motile sperm. There is a possibility that ROS produced by activated sperm affect embryogenesis following sperm incorporation, resulting in chromosomal aberration. Here, we examined sperm capacitation state, ROS production along with the developmental ability of embryos following intracytoplasmic injection of activated sperm in which mitochondrial activity had been reduced experimentally. In the first experiment, we used a luminometer to investigate ROS production by sperm treated with carbonyl cyanide m-chlorophenyl hydrazone (cccp), an uncoupler of cell respiration. In our second experiment, mitochondria integrity and activity was determined quantitatively using mitotracker red and 5, 50, 6, 60-tetrachloro-1, 10, 3, 30-tetraethylbenzimidazolyl- carbocyanine iodide (JC-1) in groups of normal motile sperm (control group), activated (Act group) sperm, and activated sperm in which mitochondrial activity had been reduced by cccp (MT group). The proportion of sperm exhibiting a characteristic pattern of capacitation was visualized by chlortetracycline staining and tyrosine phosphorylation in each experimental group. In our third experiment, we examined how sperm from each experimental group might affect developmental competence of an embryo produced by ICSI, including cleavage, development to the blastocyst stage, and chromosomal integrity of the blastocyst stage. ROS produced by mitochondria was decreased by cccp. Mitochondrial integrity, as assessed by mitotracker red was intact in all group and the proportion of active mitochondria as indicated by JC-1 was 82.4%, 83.3% and 33.3%, in the control group, Act group and MT group, respectively (P<0.05). The proportion of sperm exhibiting the characteristic pattern of capacitation, as determined by chlortetracycline staining, was 58.3%, 71.4% and 71.4% in the control group, Act group and MT group, respectively, whilst levels of tyrosine phosphorylation were 0.0%, 26.9% and 61.8% (P<0.05). There were no significant differences in the rate of embryo development to the blastocyst stage among the three groups (20.7% vs 25.0% vs 31.4% respectively, P>0.05). On the other hand, chromosomal integrity of the blastocyst stage in the MT and control groups were higher than in the Act group (78.6%:11/14 vs 86.7%:13/15 vs 7.1%:1/14, respectively, P<0.05). Our results indicate that suppression of mitochondorial activity in activated bovine sperm reduce ROS production but induce normal embryogenesis following ICSI. (poster)
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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 ».