Elsevier

Brain Research

Volume 1295, 12 October 2009, Pages 179-185
Brain Research

Research Report
Anterior circulation mouse model of subarachnoid hemorrhage

https://doi.org/10.1016/j.brainres.2009.08.021Get rights and content

Abstract

A model of subarachnoid hemorrhage (SAH) first described in rats where blood is injected into the prechiasmatic cistern was adapted to mice. The hypothesis was that such an anterior circulation SAH model would produce vasospasm of greater severity and longer duration than other mouse models. The goal was to create a mouse model that could then be used in transgenic and knockout animals in order to further knowledge of SAH and vasospasm. A needle was inserted stereotactically into the prechiasmatic cistern and 100 µl autologous arterial blood injected over seconds (n = 10). Effects were compared to injection of saline (n = 10) or to sham operation (n = 7). Monitoring of cerebral blood flow by laser Doppler showed a statistically similar decrease during injection in both groups. 7 days after SAH there was vasospasm of the middle and anterior cerebral arteries (51% reduction in MCA radius in SAH compared to saline-injected group, P < 0.009, Student's t-test). In order to determine if SAH in this model was associated with neuronal injury, brains were examined for TUNEL and fluoro-jade-positive cells. 60% of SAH but not saline-injected mice exhibited TUNEL-positive cells in the cerebral cortex and 30% of the SAH but no saline-injected mice had fluoro-jade positive cells in the cortex, hippocampus and dentate gyrus. The model is simple to perform and may be useful for investigating the pathophysiology of SAH.

Introduction

Subarachnoid hemorrhage (SAH) comprises only about 7% of all strokes worldwide but is associated with a disproportionate morbidity, mortality and cost to society due to the relatively young age of patients affected, among other reasons (Taylor et al., 1996). SAH is characterized by spontaneous bleeding into the subarachnoid space caused by trauma or rupture of intracranial aneurysms. Many experimental models have been used to investigate SAH (Megyesi et al., 2000). Each has advantages and disadvantages. Large animal models in dogs and nonhuman primates accurately produce vasospasm but not the acute effects of SAH itself, and are expensive, time-consuming and not amenable to molecular manipulations. Rodent models have the opposite problems. SAH in rodents has been created by injecting blood into the cisterna magna or by endovascular perforation of the anterior circulation intracranial arteries (Bederson et al., 1995, Delgado et al., 1985, Megyesi et al., 2000, Solomon et al., 1985).

One promising adaptation of the rat model was changing the blood injection site from the cisterna magna to the chiasmatic cistern (Prunell et al., 2002). Since approximately 80% of aneurysmal SAH are caused by ruptured aneurysms located in the anterior circulation (Kassell et al., 1990, Velthuis et al., 1998), this model may recreate the clinical setting more accurately. This model also may reduce variability compared to endovascular perforation models by injecting a standard amount of blood and by allowing repeatable increases in intracranial pressure (ICP) that can reflect what happens in humans (Prunell et al., 2002).

Here we take advantage of the pre-chiasmatic injection technique to create a mouse model that mimics human SAH. We show that several common complications associated with SAH such as cerebral vasospasm and delayed neuronal death occur in this model.

Section snippets

Mortality

Mortality occurred in 10% (1 of 10) of mice undergoing SAH. Death was in the first day after SAH. There was no mortality more than 1 day post-SAH or in any saline-injected or sham-operated animals.

CBF

In sham-operated mice, there were no changes in CBF after the insertion of the needle (Fig. 1). SAH and saline-injected animals showed a steep drop in CBF seconds after the injection. Raw CBF data of tissue perfusion units (TPU) were standardized to baseline, and expressed as percent change from an

Discussion

Designing an ideal experimental model for SAH remains problematic; however criteria listed by Schwartz et al., suggest that an ideal model should be reproducible with little interanimal variation, have blood dispersion that mimics aneurysmal rupture, be simple and inexpensive, produce a controlled degree of hemorrhage and reproduce the clinical complications of SAH such as cerebral vasospasm (Schwartz et al., 2000). The mouse model reported here meets most of these criteria, and therefore, may

Animal model

Experimental protocols were approved by the Institutional Animal Care Committee. 27 male CD1 mice weighing 33 to 40 g were used. They were anesthetized with ketamine (10 mg/kg) and xylazine (4 mg/kg) intraperitoneally. Body temperature was maintained at 37.0 ± 0.5 °C with a rectal temperature probe and homeothermic heating pad (Harvard apparatus, Holliston, Massachusetts).

For creation of SAH, the head was fixed in a stereotactic frame equipped with a mouse adaptor (Harvard apparatus). Stereotactic

Acknowledgments

Supported by grants from Physicians Services Incorporated Foundation and the Brain Aneurysm Foundation.

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