Background:
Majority of aneurysmal subarachnoid hemorrhage (SAH) survivors develop cognitive dysfunction. To better understand the underlying mechanisms and develop treatments, predictive animal models are required. We carried out a detailed physiological and cognitive characterization of pre-chiasmatic cistern (PC) and cisterna magna (CM) SAH models in mice.
Methods:
SAH was induced by arterial blood injection into the PC (40 μl) or CM (60 μl) in C57BL6/J mice (male, 25g). Controls received normal saline. Cerebral blood flow (CBF) was imaged using laser speckle flowmetry during and for 60 min after SAH. Intracranial pressure (ICP) and blood pressure (BP) were monitored to calculate cerebral perfusion pressure (CPP). Neurological and cognitive function was assessed 3 weeks after the injection, using pole, novel object recognition, Y maze and Morris water maze tests.
Results:
Mortality was 10% after PC and 4% after CM SAH. In both groups, CPP decreased from about 65 mmHg to less than 10 mmHg immediately after the injection, and recovered to 40 mmHg within 10 min after PC (n=8) and 7 min after CM (n=8) SAH (Fig A). In both groups, CBF was severely reduced to ~20% of baseline in both hemispheres immediately after SAH. CBF recovered to >40% within 5 min after PC and 2 min after CM SAH (Fig A). In saline controls (n=5 in PC and CM each), CPP and CBF changes were much milder and shorter-lasting. Compared with controls (n=12), PC SAH mice (n=12) performed significantly worse in a subset of sensorimotor and cognitive tests for up to 3 weeks (Fig B). CM SAH did not significantly impact neurological function.
Conclusions:
Pre-chiasmatic cistern but not cisterna magna SAH model reproduces cognitive dysfunction observed in patients with low mortality and high reproducibility in mice.
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