Training of late middle aged rats increases oxidative capacity without increasing mitochondrial content
Bibliographic record
Abstract
There is some evidence that aged muscle does not increase mitochondrial protein content after exercise training, suggesting an improvement in mitochondrial quality rather than quantity. The purpose of this study was to determine if an improvement in oxidative capacity without an increase in mitochondrial content also occurs in a rat model, and to investigate one of the markers involved in mitochondrial biogenesis. Late middle aged (28 mo; 70% survival rate) Fisher 344‐BN male rats performed treadmill running exercise 5 times/wk for 7 wk and were compared to an age‐matched sedentary group. Muscle aerobic performance was assessed using a pump‐perfused hindlimb model. Contralateral gastrocnemius and plantaris muscles were harvested for biochemical and molecular measurements. Endurance training increased muscle VO 2 max (15%) and citrate synthase and complex IV activity (~25%) compared to the control group. CS protein content was not significantly different between training and sedentary groups, suggesting that mitochondrial content did not increase with training. PGC‐1α protein but not mRNA was increased only in the plantaris muscle with training. These results show that endurance training of late middle aged rats increases oxidative enzyme activity without an increase in protein content. The training‐induced improvement in mitochondrial function but not content may occur secondary to increased mitochondrial turnover. Supported by CIHR and the Alberta Provincial CIHR Training Program in Bone and Joint Health
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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 | 0.000 | 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".