Suppression of Mitochondrial Activity in Activated Bovine Sperm Advances Capacitation Status and Induces Normal Embryogenesis.
Bibliographic record
Abstract
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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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".