Direct Single Injection of p38 Mitogen-Activated Protein Kinase Inhibitor Does Not Affect Calcitonin Gene-Related Peptide Expression in Dorsal Root Ganglion Neurons Innervating Punctured Discs in Rats
Bibliographic record
Abstract
STUDY DESIGN.: Immunohistological analysis of punctured disc after application of a p38 MAP kinase inhibitor. OBJECTIVE.: To examine effect of direct application on dorsal root ganglion (DRG) neurons innervating damaged rat discs. SUMMARY OF BACKGROUND DATA.: Degeneration of lumbar discs is one cause of low back pain. Pathogenesis may involve sensory nerve ingrowth into disc inner layers; tumor necrosis factor-alpha (TNF-alpha) is thought to be a major inducer of ingrowth. Because p38 mitogen-activated protein kinase (p38) upregulates TNF-alpha expression and may play a crucial role in pain sensation, we investigated the effect of one injection of inhibitor on expression of the pain-related neuropeptide calcitonin gene-related peptide (CGRP). METHODS.: The neuro-tracer fluoro-gold was applied to the surfaces of L4/5 discs to label the innervating DRG neurons (n = 30). Of 30 rats, 10 were controls, whereas the other 20 were the experimental model (i.e., discs were punctured with 23-gauge needle). P38 specific inhibitor or saline was applied simultaneously (n = 10 each, Puncture + inhibitor and puncture + saline groups). Fourteen days postsurgery, DRGs from L1 to L6 were harvested, sectioned, and immunostained for CGRP. Proportion of CGRP-immunoreactive DRG neurons was evaluated in all groups. RESULTS.: Fluoro-gold-labeled neurons innervating the L4/5 disc were distributed throughout L1 to L6 DRGs in all groups. Proportions of labeled neurons positive for CGRP were 15.2% +/- 8% (controls), 27.2% +/- 10% (puncture + saline), and 25.2% +/- 8% (puncture + inhibitor). Proportion of immunoreactive neurons was significantly increased in the puncture groups compared with controls. However, there was no significant difference between the 2 puncture groups (P > 0.1). CONCLUSION.: In this model, CGRP was upregulated in DRG neurons innervating the damaged disc. However, a direct single application of p38 inhibitor did not suppress CGRP expression in innervating DRG neurons. Future research with p38 inhibitor in this model should evaluate multiple or systemic administration of inhibitor.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".