Chronic post-ischemia pain (CPIP): a novel animal model of complex regional pain syndrome-Type I (CRPS-I; reflex sympathetic dystrophy) produced by prolonged hindpaw ischemia and reperfusion in the rat
Bibliographic record
Abstract
A neuropathic-like pain syndrome was produced in rats following prolonged hindpaw ischemia and reperfusion, creating an animal model of complex regional pain syndrome-Type I (CRPS-I; reflex sympathetic dystrophy) that we call chronic post-ischemia pain (CPIP). The method involves placing a tourniquet (a tight fitting O-ring) on one hindlimb of an anesthetized rat just proximal to the ankle joint for 3 h, and removing it to allow reperfusion prior to termination of the anesthesia. Rats exhibit hyperemia and edema/plasma extravasation of the ischemic hindpaw for a period of 2-4 h after reperfusion. Hyperalgesia to noxious mechanical stimulation (pin prick) and cold (acetone exposure), as well as mechanical allodynia to innocuous mechanical stimulation (von Frey hairs), are evident in the affected hindpaw as early as 8 h after reperfusion, and extend for at least 4 weeks in approximately 70% of the rats. The rats also exhibit spontaneous pain behaviors (hindpaw shaking, licking and favoring), and spread of hyperalgesia/allodynia to the uninjured contralateral hindpaw. Light-microscopic examination of the tibial nerve taken from the region just proximal to the tourniquet reveals no signs of nerve damage. Consistent with the hypothesis that the generation of free radicals may be partly responsible for CRPS-I and CPIP, two free radical scavengers, N-acetyl-L-cysteine (NAC) and 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxyl (Tempol), were able to reduce signs of mechanical allodynia in this model.
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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) | 0.002 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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".