7,12-Dimethylbenz[a]anthracene-Induced Ovotoxicity Following a Single Exposure in Rat Ovaries.
Bibliographic record
Abstract
The polycyclic aromatic hydrocarbon 7, 12-dimethylbenz[a]anthracene (DMBA) is a source of environmental exposure in cigarette smoke, automobile exhaust, and combustion by-products. It destroys all follicle types in the rat ovary. Cultured postnatal day 4 (PND4) F344 rat ovaries exposed on alternate days to DMBA at concentrations ranging from 12.5 nM to 1000 nM for 15d had reduced (P < 0.05) primordial follicle numbers at concentrations ≥ 75 nM. This study investigated the effect of single DMBA exposures on rat ovarian follicle numbers. PND4 F344 rat ovaries were cultured in control medium for 4d to allow development of large primary and secondary follicles prior to DMBA exposure. Ovaries then received single exposures to vehicle control (DMSO; CT) or DMBA at concentrations where primordial follicle loss has (75 nM) and has not (12.5 nM) been previously observed. Histological evaluation was performed 8d after treatment and follicle types were classified and counted. There was no effect (P > 0.05) of DMBA exposure on primordial (CT - 176.7 ± 50.7; DMBA 12.5 nM - 190.5 ± 70.3; DMBA 75 nM - 220 ± 8.7), or small primary (CT - 187.3 ± 21.5; DMBA 12.5 nM - 120 ± 41.9; DMBA 75 nM - 221.3 ± 22.9) follicles. In contrast, single exposures of DMBA at both concentrations depleted (P < 0.05) large primary follicles (CT - 42.67 ± 3.5; DMBA 12.5 nM - 14.3 ± 7.2; DMBA 75 nM - 27.7 ± 2.6), but interestingly, only the 12.5 nM DMBA concentration reduced (P < 0.05) secondary follicle numbers (CT - 13.7 ± 1.5; DMBA 12.5 nM - 2 ± 1.4; DMBA 75 nM - 17 ± 3.2). The reason for lack of secondary follicle loss with a higher DMBA exposure may be due to induction of detoxification enzymes. Thus, ovaries are more sensitive to multiple rather than single DMBA exposures, but it is likely that single exposures at higher DMBA concentrations would affect all follicle types. In summary, exposing ovaries that contain increased numbers of large pre-antral follicles to DMBA demonstrated loss of large primary and secondary follicles. Collectively, these results raise concern over single or low-level cumulative exposures of DMBA for female ovarian function and support the use of the rat ovary culture system for mechanistic studies on DMBA-induced ovotoxicity.(Supported by ES016818 to AFK, ES09246 to PBH and Center grant ES06694). (poster)
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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 | 0.000 | 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) | 0.000 | 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".