Development of a Rodent Spinal Cord Injury Model Permissive to Study the Cardiovascular Effects of Rehabilitation Approaches Designed to Induce Neuroplasticity
Bibliographic record
Abstract
Background and Aims Spinal cord injury (SCI) induced dysregulation of the cardiovascular (CV) system occurs primarily due to altered descending control over the sympathetic preganglionic neurons. Within the somatic nervous system, the development of pre‐clinical models of SCI has provided researchers with a powerful tool to study the effects of neuroplasticity on functional outcomes. To date, a similar pre‐clinical model that spares sufficient descending sympathetic pathways to enable the study of neuroplasticity within the sympathetic nervous system but still induces a substantial decline in cardiac and hemodynamic function has not been forthcoming. To address this need we developed a moderately‐severe midline contusion injury model at the T3 spinal level, measured in vivo hemodynamic and cardiac function invasively via catheterization, and quantified lesion site characteristics. Methods A total of 36 Wistar rats were assigned to either SCI (n=13) or naive (n=23) groups. For spinal cord contusion, animals were initially anesthetized with isoflurane then a dorsal midline incision was made and paraspinal musculature bluntly dissected. T3 laminectomy was performed and the animals were injured at the T3 spinal segment using an Infinite Horizon impactor with 300 kdyn of force. At 14 days post‐SCI, left‐ventricular and arterial catheterization was performed to assess in vivo cardiac and hemodynamic function. Following in vivo measures, the spinal cord was harvested, cut, and stained to determine lesion site characteristics via immunohistochemistry. Between‐group differences in all outcomes were analyzed using an independent samples t ‐test. Statistical significance was set at p<0.05. Results SCI produced a decrease in left ventricular maximum pressure (LV max ) (naive=120±9 mmHg vs SCI=99±12 mmHg, p<0.001) and maximal left ventricular pressure rise (dP/dt max ) (9984±1049 vs. 6101±787 mmHg/s, p<0.001), arterial systolic blood pressure (127±14 vs. 97±10 mmHg, p<0.001), diastolic blood pressure (76±11 vs. 57±8 mmHg, p<0.001) and mean arterial pressure (93±12 vs. 69±8 mmHg, p<0.001). Immunohistological staining and visualization of the epicenter of the cord revealed 17±4% tissue sparing. Conclusions Our novel 300 kdyn contusion SCI produced significant decreases in cardiac and hemodynamic function while preserving 15‐20% of tissue at the epicentre. Additionally, this injury model eased the burden of care compared to more severe injury models that are traditionally used in CV studies post‐SCI. These findings suggest that our novel 300 kdyn contusion injury is a useful pre‐clinical model of SCI to study rehabilitation approaches designed to induce neuroplasticity.
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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 | 0.001 | 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 | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".