Dexamethasone treatment of post-MI rats attenuates sympathetic innervation of the infarct region
Bibliographic record
Abstract
Sympathetic fiber innervation of the damaged region following injury represents a conserved event of wound healing. The present study tested the hypothesis that impaired scar healing in post-myocardial infarction (post-MI) rats was associated with a reduction of sympathetic fibers innervating the infarct region. In 1-wk post-MI rats, neurofilament-M-immunoreactive fibers (1,116 +/- 250 microm(2)/mm(2)) were detected innervating the infarct region and observed in close proximity to a modest number of endothelial nitric oxide synthase-immunoreactive scar-residing vessels. Dexamethasone (Dex) treatment (6 days) of post-MI rats led to a significant reduction of scar weight (Dex + MI 38 +/- 4 mg vs. MI 63 +/- 2 mg) and a disproportionate nonsignificant decrease of scar surface area (Dex + MI 0.54 +/- 0.06 cm(2) vs. MI 0.68 +/- 0.06 cm(2)). In Dex-treated post-MI rats, the density of neurofilament-M-immunoreactive fibers (125 +/- 47 microm(2)/mm(2)) innervating the infarct region was significantly reduced and associated with a decreased expression of nerve growth factor (NGF) mRNA (Dex + MI 0.80 +/- 0.07 vs. MI 1.11 +/- 0.08; P < 0.05 vs. MI). Previous studies have demonstrated that scar myofibroblasts synthesize NGF and may represent a cellular target of Dex. The exposure of 1st passage scar myofibroblasts to Dex led to a dose-dependent suppression of [(3)H]thymidine uptake and a concomitant attenuation of NGF mRNA expression (untreated 3.47 +/- 0.35 vs. Dex treated 2.28 +/- 0.40; P < 0.05 vs. untreated). Thus the present study has demonstrated that impaired scar healing in Dex-treated post-MI rats was associated with a reduction of neurofilament-M-immunoreactive fibers innervating the infarct region. The attenuation of scar myofibroblast proliferation and NGF mRNA expression may represent underlying mechanisms contributing to the diminished neural response in the infarct region of Dex-treated post-MI rats.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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) | 0.000 | 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 teacher head, 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".