A new grading system evaluating bleeding scale in filament perforation subarachnoid hemorrhage rat model

Area of Science:

• Neuroscience
• Experimental Neurology
• Animal Models

Background:

• The endovascular perforation rodent model for experimental subarachnoid hemorrhage (SAH) lacks control over bleeding, hindering severity assessment.
• A practical grading system for SAH severity based on blood volume is currently unavailable for experimental models.

Purpose of the Study:

• To introduce a novel, simple, and objective grading system for SAH severity in rodent models.
• To evaluate the correlation of this grading system with neurological status and cerebral vasospasm.
• To assess the efficacy of simvastatin in mitigating SAH effects using the developed grading system.

Main Methods:

• Seventy-seven Sprague-Dawley rats were divided into sham-operated, SAH, and SAH+simvastatin groups.
• High-resolution brain imaging was used to grade SAH severity (mild, moderate, severe) based on subarachnoid blood clots in basal cisterns.
• Neurological scores and internal carotid artery parameters were assessed at 24 hours and correlated with SAH grades.

Main Results:

• The SAH grading system demonstrated a significant linear correlation with neurological status (r=0.42, p<0.01) and vasospasm (absolute r>0.7, p<0.01).
• Independent verification showed high inter-rater reliability (r=0.937, p<0.001).
• Simvastatin treatment improved neurological scores in moderate and severe SAH groups but not in mild SAH.

Conclusions:

• The developed SAH grading system provides an objective and reliable method for assessing bleeding severity in rodent models.
• This system effectively correlates with functional neurological deficits and morphometric evidence of cerebral vasospasm.
• The grading system has potential for widespread adoption in experimental SAH research.