Characteristics of Sustained Blood-Brain Barrier Opening and Tissue Injury in a Model for Focal Trauma in the Rat
Bibliographic record
Abstract
Minor stab wounding of rodent brain by needle or razor blade is a standard model for immunohistochemical investigations of secondary neuronal degeneration and scarring. Opening of the blood-brain barrier (BBB) to plasma molecules and inflammatory cells is integral to the secondary injury process. To facilitate quantitative study of these BBB phenomena, we tested the utility of a stereotaxic wire knife as a minimally invasive way for modeling of focal trauma and bleeding in brain parenchyma and substantial, reproducible BBB damage. Adult rats were anesthetized, and through a skull burr hole, the 0.3-mm dia guide cannula housing a laterally extendable tungsten wire (0.13 mm dia) was inserted into the right striatum. A layering of horizontal disk-like cuts (3 mm dia) was made, producing a cylindrical lesion of approximately 18 mm3 volume, approximately 2.7% of the cerebral hemisphere. Transfer constants (Ki) for blood to brain permeation of [3H]sucrose measured from 30 min to 2 weeks postlesion showed sustained BBB leakiness; for example, mean Ki +/- SEM (nL.g(-1) x s(-1)) for a standard, matrix-dissected forebrain sample enclosing the lesion were 7.2 +/- 1.2 (day 1 postlesion), 8.1 +/-1.4 (day 3), 5.4 +/- 0.8 (day 14) compared with values for contralateral nonlesioned forebrain ranging from 1.3 +/- 0.05 to 1.6 +/- 0.3 (n = 3-4 samples per time point). Analysis of the simultaneous transport of [14C]sucrose (MW = 342 Da) and [3H]inulin (MW approximately 5,000) showed significantly larger upward increments in Ki for sucrose than inulin, indicating a pore-like opening mechanism. Significant edema was measured 3 days postlesion. A reactive glial response was indicated by an increase in S100beta by 6 h and a glial scar forming around the lesion by 7 days. Secondary brain injury was indicated by a 10% loss of hemisphere mass, measured at 2 months. The wire knife enabled tailoring of interstitial trauma with a minimum of extraneous injury and supported reproducible measurements of sustained BBB injury using relatively few animals.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 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".