Repeated Mifepristone And Polyethylene Glycol Exposure Prevent Intestinal Lymphocyte Loss After Treadmill Exercise In Mice
Bibliographic record
Abstract
0910 Strenuous physical exercise is associated with lymphocytopenia and compromised immune function. Glucocorticoids (GC) and oxidative stress (ROS) produced by exercise are two factors that may be responsible for this lymphocyte cell loss. Purpose: To determine if the GC receptor antagonist mifepristone (MIF) and polyethylene glycol (PEG), commonly used for MIF solubilization and which inhibits ROS production and repairs membrane damage, prevent exercise-induced intestinal lymphocyte cell loss. Methods: One hundred and fifty-three female C57BL/6 mice were given (i) a single s.c. injection of control solution (vehicle), (ii) a single injection of MIF, (iii) repeated injections of MIF solubilized in PEG, or (iv) repeated injections of PEG. Following injection mice were exposed to 90 min of treadmill exercise (28m·min−1, 2° slope) and sacrificed immediately or 24h after exercise. Control mice were exposed to treadmill noise and vibration without running. Following sacrifice intestinal lymphocytes (IL) were isolated and analysed for T and natural kill (NK) subpopulations using flow cytometry. Plasma corticosterone (CORT) was determined by RIA. Results: Plasma CORT was significantly elevated in repeated MIF, nonexercised mice (mean ± SEM; 126.8 ± 3.9ng·ml−1) compared with vehicle (67.9 ± 2.9ng·ml−1), single MIF (77.1 ± 6.8ng·ml−1) and PEG (61.7 ± 6.6ng·ml−1) injected mice (p < 0.001). After exercise there was a significant decrease in total IL recovered from the bowel as well as in CD3+, CD3γδ+, CD8+, CD4+ subsets in vehicle and single MIF conditions. This exercise-associated cell loss was not observed following repeated MIF and PEG injections. However, repeated MIF and PEG failed to inhibit the exercise-associated loss in NK+ cells isolated from the intestine 24h post-exercise. Conclusion: Postexercise IL, but not NK cells, depletion may be mediated by oxidative stress rather than directly by GC: repeated MIF (solubilized in PEG) and PEG alone attenuated the post-exercise drop in cell numbers whereas vehicle and single MIF were associated with pronounced IL depletion. Further studies are needed to confirm whether oxidative stress is the underlying mechanism for depletion in intestinal lymphocytes 24h after exercise. Research supported by a grant from NSERC Canada (LHG).
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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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".