Altered molecular metabolism of knee joint tissues in a botox induced quadriceps muscle weakness model in the rabbit
Bibliographic record
Abstract
Background Muscle weakness due to joint injuries (eg, anterior cruciate ligament rupture) or muscle injuries (eg, muscle strain) are very frequent in sports. Objective To analyze changes to knee joint ligaments and menisci induced by quadriceps muscle weakness by measuring molecular metabolism. Design Prospective randomised controlled trial. Setting Laboratory study. Interventions Chronic quadriceps muscle weakness was induced in six 1-year old New Zealand White rabbits through monthly injections of Botox (botulinum toxin A) for six months. Five age- and sex-matched rabbits served as controls. Main outcome measurements Muscle weakness was assessed by measuring muscle weight, isometric quadriceps force, and histologic muscle degeneration. Molecular metabolism was measured in the patellar tendon, medial and lateral collateral ligaments, and medial and lateral menisci by measuring total RNA yields, and nine tissue specific RNA yields (eg, Collagen I, MMP-III). Results Muscle weights were decreased by 46.6%, muscle forces by 58.6 to 61.3% depending on the knee flexion angle, and cross sectional areas of the contractile apparatus by 54.7% (all results p<0.001) for the test—compared to the control group animals. Molecular analysis showed significantly decreased overall turnover (MMP-I), and significantly decreased metabolism for anabolic factors (Collagen I, MMP-III, MMP-XIII, TGFâ) and reduced injury response (Collagen III, MMP-XIII). Discussion Quadriceps muscle weakness leads to adaptive changes in knee joint structures by adjusting specific RNA activities while overall cell metabolism remains unchanged. In the concept of the joint as an organ, this may reflect a new functional steady-state. Muscular unloading of the knee might impair the biomechanical function of the knee joint and its component structures. This could describe an underlying pathomechanism of the fact, that injured athletes are more susceptible to additional overuse injuries than healthy athletes. Therefore, we suggest that weaknesses of muscles and component joint structures being considered in injury treatment and rehabilitation.
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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 | 0.003 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".