Therapeutic benefits of the methyl donor S-adenosylmethionine on nerve injury–induced mechanical hypersensitivity and cognitive impairment in mice
Bibliographic record
Abstract
Despite considerable advances in understanding mechanisms involved in chronic pain, effective treatment remains elusive. Comorbid conditions including anxiety, depression, and cognitive impairment further impact quality of life. Chronic pain is associated with reversible changes in brain anatomy and function and with long-term changes in gene expression. Epigenetic mechanisms, including DNA methylation, contribute to wide-spread and long-lasting reprogramming of gene expression. We previously reported decreases in global DNA methylation in the mouse frontal cortex 6 months after induction of neuropathic pain using the spared nerve injury (SNI) model. Here, we examined the therapeutic effect of increasing DNA methylation using the methyl donor S-adenosylmethionine (SAM). S-adenosylmethionine is marketed as a nutritional supplement for a range of conditions including liver disease, depression, osteoarthritis, fibromyalgia, and dementia. Three months after SNI or sham surgery, animals were treated with SAM (20 mg/kg, 3×/week) or saline orally for 4 months, and the impact on sensory, motor, motivational, and cognitive indices was measured. S-adenosylmethionine attenuated SNI-induced mechanical hypersensitivity and reduced active avoidance of mechanical stimuli but had no effect on cold sensitivity or motor capacity. S-adenosylmethionine completely blocked nerve injury-induced cognitive impairment and attenuated SNI-induced decreases in global DNA methylation in the frontal cortex. In summary, chronic oral administration of the methyl donor, SAM, attenuated sensory and cognitive symptoms associated with nerve injury in mice. These effects may be mediated, in part, through modulation of DNA methylation in the central nervous system by systemic administration of the methyl donor SAM.
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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 | 0.002 |
| Insufficient payload (model declined to judge) | 0.002 | 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".