A Quantitative Assessment of the Changes in the Molecular Phenotype of the Rat Tail Intervertebral Disc Induced by Stereotactic, Image-Guided Needle Puncture
Notice bibliographique
Résumé
Introduction A significant obstacle to the study of degenerative disc disease and therapeutic strategies to treat DDD has been the lack of a suitable animal model. Here, we detail a mechanistic investigation of the changes in the molecular phenotype of the cells within the intervertebral disc in a preclinical rodent model of IVD degeneration following needle puncture. Material and Methods Using a stereotactic device and fluoroscopic imaging control, we injured four IVDs/tail using 12-week-old female wistar rats and a 26-gauge needle. The needle was directed completely through the IVD annulus fibrosus (AD) to emerge through the contralateral annulus. The needle was then retracted back into the NP and after 1 minute, the needle was slowly removed over a further minute. The animals were allowed to recover for 10 weeks following which they were humanely euthanized and the discs recovered for biochemical, immunohistochemical, and protein analysis (Western blots). Results The healthy rat NP changes drastically 10-weeks following needle puncture injury such that the former notochordal cell-rich NP assumes a fibrocartilaginous phenotype by 10 weeks. Initially, there is an increase in the expression of the notochordal cell markers galectin-3 and brachyury beginning at 72 hours; however, these are undetectable by 10 weeks with only scant appearance of immunopositive cells. Before injury, there are barely detectable chondrocyte-like cell (CLC) markers such as carbonic anhydrase-12 and Sox9, however, following injury there is a steady increase in their expression maximizing by 4 to 8 weeks. The strong expression of the stemness marker Oct3/4 steadily increases its expression post injury that reaches a peak at 6 weeks; however, this stemness marker is undetectable at 10 weeks. A similar trend is seen with the cell signaling protein β-catenin that is barely detectable at baseline but is strongly expressed at 72 hours postinjury and steadily increases until 4 weeks and then decreases to lower level expression at 10 weeks. There is an increase in the expression of collagen types 1 and 2 beginning 72 hours postinjury with a continued increase through 10 weeks. Interestingly, there is a reciprocal relationship between the matrix metalloproteinases (MMPs) and the tissue inhibitors of MMPs (TIMPS). MMP-3 and MMP-13 become detectable at 8 to 10 weeks precisely following the steady increase in expression of the natural inhibitor TIMP-1 which is completely undetectable when MMP-3 and MMP-13 increase their expression. ADAMTS-4 gradually increases its expression beginning at 72 hours through 8 weeks but is undetectable at 10 weeks. Conclusion Here, for the first time, we present a novel method of inducing degeneration in the rat tail IVD disc and have quantified the changes in the molecular phenotype of the IVD over 10 weeks. The injured rat tail IVD goes through a significant alteration in cellular and extracellular configuration that suggests a failed attempt on the part of notochordal and stem cells to induce repair resulting in the development of a fibrocartilaginous NP. This animal model and our characterization in the changes that causes postinjury can be used to quantify the effects of potential biological therapies in the treatment of DDD.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».