Identifying germ cell mutagens using OECD test guideline 488 (transgenic rodent somatic and germ cell gene mutation assays) and integration with somatic cell testing
Bibliographic record
Abstract
The Organisation for Economic Co-operation and Development Test Guideline 488 (TG 488) provides recommendations for assessing germ cell and somatic cell mutagenicity using transgenic rodent (TGR) models. However, important data gaps exist for selecting an optimal approach for simultaneously evaluating mutagenicity in both cell types. It is uncertain whether analysis of germ cells from seminiferous tubules (hereafter, tubule germ cells) or caudal sperm within the recommended design for somatic tissues (i.e., 28 days of exposure plus three days of fixation time, 28 + 3d) has enough sensitivity to detect an effect as compared with the analysis of sperm within the recommended design for germ cells (i.e., 28 + 49d and 28 + 70d for mouse and rat, respectively). To address these data gaps, the Germ Cell workgroup of the Genetic Toxicology Technical Committee of the Health and Environmental Sciences Institute reviewed the available TGR mutagenicity data in male germ cells, and, characterized the exposure history of tubule germ cells for different sampling times to evaluate its impact on germ cell mutagenicity testing using TG 488. Our analyses suggest that evaluating mutant frequencies in: i) sperm from the cauda epididymis at 28 + 3d does not provide meaningful mutagenicity data; ii), tubule germ cells at 28 + 3d provides reliable mutagenicity data only if the results are positive; and iii) tubule germ cells at 28 + 28d produces reliable positive and negative results in both mice and rats. Thus, the 28 + 28d regimen may provide an approach for simultaneously assessing mutagenicity in somatic tissues and germ cells from the same animals. Further work is required to support the 28 + 28d protocol for tissues other than slowly proliferating tissues as per current TG 488. Finally, recommendations are provided to guide the experimental design for germ cell mutagenicity data for regulatory submission, as well as other possible approaches to increase the reliability of the TGR assay.
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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 | 0.001 | 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 | 0.001 | 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".