Effects of ageing on spermatozoal chromatin and its sensitivity to in vivo and in vitro oxidative challenge in the Brown Norway rat
Bibliographic record
Abstract
BACKGROUND: The goals of our study were to examine chromatin packaging and integrity in spermatozoa taken from the caput and cauda epididymides of young (4-month-old) and old (21-month-old) Brown Norway rats and to assess whether spermatozoal sensitivity to oxidative treatments is altered with age. METHODS: Oxidative treatments consisted of (i) in vivo oxidative challenge by systemic administration of the glutathione-depleting drug l-buthionine-[S,R]-sulphoximine (BSO) and (ii) in vitro oxidative challenge by incubating collected spermatozoa with hydrogen peroxide (H(2)O(2)). Chromatin parameters assessed included quantification of thiols, nuclear chromomycin A3 (CMA3) penetration, DNA breaks by TdT (terminal deoxynucleotidyl transferase)-mediated dUDP nick-end labelling (TUNEL) and ease of DNA dissociation by acridine orange (AO) staining. RESULTS: In spermatozoa from older rats, we found decreases in thiols, CMA3 penetration and the percentage of cells that undergo DNA dissociation. Administration of BSO had oxidizing effects on the thiol groups. It also decreased CMA3 penetration and DNA dissociation and increased TUNEL staining. Furthermore, BSO treatment sensitized cauda epididymidis spermatozoa, from older animals, to H(2)O(2). CONCLUSIONS: Overall, we show that spermatozoa from older rats have altered chromatin packaging and integrity and that spermatozoa from the cauda epididymidis are more responsive to combined in vivo and in vitro oxidative challenge than spermatozoa from young rats.
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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".