Embryoprotective Role of Endogenous Catalase in Acatalasemic and Human Catalase-Expressing Mouse Embryos Exposed in Culture to Developmental and Phenytoin-Enhanced Oxidative Stress
Bibliographic record
Abstract
Reactive oxygen species (ROS) are implicated in spontaneous and xenobiotic-enhanced embryopathies, and protein therapy with exogenous catalase suggests an embryoprotective role, although embryonic catalase activity is only about 5% of adult activity. Using mutant catalase-deficient (acatalasemic, aCat) mice and transgenic mice expressing human catalase (hCat, enhanced catalase activity) compared with a confirmed outbred CD-1 mouse model, we investigated the protective importance of constitutive embryonic catalase against endogenous ROS and the ROS-initiating teratogen phenytoin in embryo culture. Vehicle-exposed aCat and hCat embryos, respectively, exhibited reduced and enhanced catalase activity compared with wild-type (WT) controls, with conversely enhanced and reduced spontaneous embryopathies. Phenytoin was embryopathic in all strains without altering catalase activity but less so in the WT embryos for the aCat and hCat strains, which exhibited about half the catalase activity of CD-1 embryos. Phenytoin, respectively, enhanced and reduced embryopathies in aCat and hCat embryos. Among aCat embryos exposed to phenytoin, embryopathies increased with decreasing catalase activity and were completely blocked by addition of exogenous catalase, which increased embryonic catalase activity to WT levels. These results provide the first direct evidence that (1) the low level of constitutive embryonic catalase protects the conceptus from developmental and xenobiotic-enhanced oxidative stress and (2) embryonic variations in activity of this enzyme affect development.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".