DIFFERENTIAL RESPONSES OF SKELETAL MUSCLE ANTI-APOPTOTIC MOLECULES 12 HOURS FOLLOWING ACUTE EXERCISE WITH AGING
Bibliographic record
Abstract
Heat shock proteins (HSPs) are a set of highly conserved polypeptides that activate several signaling pathways, some which facilitate cell survival and others that initiate cell death or apoptosis. HSP25/27 (HSP25 in mice/rats and HSP27 in humans) has been demonstrated to play a role in microfilament stabilization. However its key role, in conjunction with the HSP70 family, is to provide thermotolerance against heat stress, such as that accompanying an acute exercise session. The extent to which this protein adapts to exercise in young and aged tissue remains unclear. PURPOSE To examine the effect of aging on signaling pathways known to inhibit the apoptotic process and/or promote cell survival (HSP25/27, Akt, ERK, p70s6k) and to determine the adaptations that occur during recovery following an acute exercise session. METHODS Young and old mice were run on a motorized treadmill for 2.5 hours at speeds of 15 m/min and 8 m/min respectively. Mice were returned to their cages and sacrificed 2 hours post-exercise, hindlimb skeletal muscle removed, and subsequently analyzed for the aforementioned signaling molecules by Western blotting. RESULTS Aging alone resulted in decreasing levels of anti-apoptotic markers HSP25/27 and Akt, as well as phosphorylation of Akt (p < 0.05). Interestingly, despite lower baseline levels in aged animals, increased levels of HSP25/27 were observed following exercise in both young and old skeletal muscle. However, only young tissue appeared to have a recovery response to the exercise stimulus with increases in phosphorylation of ERK and p70s6k (p < 0.05). CONCLUSIONS These observations indicate that aged skeletal muscle lacks the response needed for cell survival and that an acute exercise bout is unable to stimulate upregulation of these molecules, with the exception of HSP25/27, in aged tissue. Increased content of HSP25/27 in both young and old muscle following exercise may be a protective mechanism in skeletal muscle for both recovery from, and preparation for, repeated stressors such as exercise.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".