EFFECT OF VOLUNTARY WHEEL RUNNING, AGE AND ESTROGEN EXPOSURE ON THYMOCYTE APOPTOSIS IN FEMALE B6D2F1 MICE
Bibliographic record
Abstract
Previous research has shown that treadmill exercise induces oxidative reactions and apoptosis in thymoyctes of young mice. It is also known that thymocytes express estrogen receptors and thymic cell function declines with age. There have been few studies, however, on the effects of physical activity, estrogen and age on thymocyte apoptosis. Young (7–8 wk of age) and older (50–52 wk of age) anestrus female B6D2F1 mice were weighed, matched by weight and randomized, separately by age, to receive estrogen (E:17βestradiol) pellets s.c.: high (H: 12μg/d), low (L: 3μg/d) and placebo (P). Females were housed individually, undisturbed, and without exposure to males, for a total of 28d. One week after pellet implantation, mice were randomly assigned to an exercise (n = 13 per group of E pellet * age) or nonexercise (n = 6 per group of E pellet * age). Exercise consisted of free access to in-cage running wheels (diameter: 22.8cm) linked to a computerized data collection system, with wheel running (WR) monitored during each 12h photoperiod. Mice were sacrificed, thymuses aseptically removed, cells counted, adjusted and stained with annexin V and propidium iodide (Beckman Coulter) for determination of %apoptosis and necrosis by flow cytometry. There were significant main effects of E exposure (p < 0.001) and age (p < 0.001), but not WR (p>0.90), on % apoptosis of thymocytes. P was associated with a lower % (mean ± SE) of apoptotic thymocytes (26.3 ± 1.5%) relative to H mice (43.5 ± 2.8%). Older female mice had a higher % of apoptotic thymocytes compared with young mice (48.1 ± 2.3% vs. 29.2 ± 1.4%). There were no significant effects of in vivo E, age or WR on the %necrosis of thymocytes in female mice. Thymic weights were higher in P mice than H or L groups (p < 0.001) and there was a trend for WR mice to have lower thymic weights than non-running controls (p = 0.079). These data suggest that in vivo exposure to high levels of estrogen increases apoptosis in the thymus and this effect occurs in young and older animals; WR, however, does not influence the induction of apoptosis of thymocytes associated with high estrogen exposure in vivo. Supported by NSERC of Canada.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".