Cartilage tissue enhances proteoglycan retention by nucleus pulposus cells in vitro
Bibliographic record
Abstract
OBJECTIVE: To investigate the effect of cartilage on nucleus pulposus (NP) tissue in an in vitro model. METHODS: Cells were isolated from bovine NP or articular cartilage and allowed to form tissue in vitro. The NP tissue was grown either alone or in the presence of cartilage tissue (coculture) for up to 4 weeks and examined for histologic appearance, gene expression, and biochemical composition. For selected experiments, NP tissue was grown in coculture with fragments of cartilage end-plate. RESULTS: Coculture of in vitro-formed NP tissue with cartilage end-plate tissue resulted in a significant increase in proteoglycan content in the NP tissue by 2 weeks, compared with NP tissue grown alone. Substituting in vitro-formed cartilage tissue for cartilage end-plate also had a positive effect on the NP tissue, suggesting that it was an appropriate substitute for cartilage end-plate. Coculture of NP with in vitro-formed cartilage for 2 weeks increased aggrecan and collagen gene expression compared with that in NP tissue grown alone, and also reduced expression of matrix metalloproteinase 3 (MMP-3), MMP-13, and ADAMTS-5. NP cells from older and younger animals responded similarly to in vitro-formed cartilage. Expression of genes for tumor necrosis factor α (TNFα) and TACE in NP cells was higher when grown in the absence of cartilage. This corresponded with increased TNFα protein levels in the absence of cartilage. CONCLUSION: The data suggest that chondrocytes may secrete a factor(s) that positively enhances tissue growth, perhaps by inhibiting TNFα production. This could be a potential mechanism explaining how loss of the cartilage end-plate may contribute to the development of NP degenerative changes.
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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 | 0.000 | 0.000 |
| 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".