Pregnancy affects cellular activity, but not tissue mechanical properties, in the healing rabbit medial collateral ligament
Bibliographic record
Abstract
Recently, evidence has been accumulating that ligament and joint laxity is altered in women and rabbits during pregnancy. Furthermore, many female adolescents injure ligaments through participation in athletics and other activities. Therefore, to determine whether pregnancy has different effects on the injured and uninjured medial collateral ligament of the rabbit knee, we investigated cellular changes (mRNA levels) and alterations in tissue properties (biomechanics) accompanying pregnancy in animals with the medial collateral ligament injured during adolescence and bred for their primigravid pregnancy as young adults. Assessment of mRNA levels for matrix molecules, matrix metalloproteinases and tissue inhibitor of metalloproteinase-1, growth factors and sex hormone receptors, inflammatory cytokines, inducible nitric oxide synthase, and cyclooxygenase-2 by semiquantitative reverse transcription-polymerase chain reaction revealed that pregnancy had different impacts on scar and uninjured tissue for six of 15 genes assessed. A pregnancy-associated increase in laxity of the medial collateral ligament was observed for rabbits in the uninjured primigravida group; however, no increase was observed for injured rabbits during pregnancy. The injured ligament was already significantly more lax than the normal counterpart, and pregnancy did not lead to additional laxity or prevent the normal decline in laxity as the scar matured in nonpregnant animals. These results indicate that the impact of pregnancy on laxity and cell activity of the medial collateral ligament is dependent on whether the ligament is uninjured or injured. Pregnancy had no significant effect on structural (stiffness and failure load), material (stress at failure and Young's modulus), or viscoelastic (cyclic and static relaxation) properties of tissue from uninjured or injured medial collateral ligament. Therefore, the properties of the healing ligament were not adversely affected during pregnancy in this experimental model. However, it remains to be determined if these results with an injured medial collateral ligament can be extrapolated to the injured anterior cruciate ligament.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".