Double Direct Injection of Blood into the Cisterna Magna as a Model of Subarachnoid Hemorrhage

Summary

We described in this protocol a standardized subarachnoid hemorrhage (SAH) mouse model by a double injection of autologous whole-blood into the cisterna magna. The high degree of standardization of the double-injection procedure represents a middle-to-acute model of SAH with relative safety regarding mortality.

Abstract

Among strokes, subarachnoid hemorrhage (SAH) consecutive to the rupture of a cerebral arterial aneurysm represents 5-9% but is responsible for about 30% of the total stroke-related mortality with an important morbidity in terms of neurological outcome. A delayed cerebral vasospasm (CVS) may occur most often in association with a delayed cerebral ischemia. Different animal models of SAH are now being used including endovascular perforation and direct injection of blood into the cisterna magna or even the prechiasmatic cistern, each exhibiting distinct advantages and disadvantages. In this article, a standardized mouse model of SAH by double direct injection of determined volumes of autologous whole blood into the cisterna magna is presented. Briefly, mice were weighed and then anesthetized by isoflurane inhalation. Then, the animal was placed in a reclining position on a heated blanket maintaining a rectal temperature of 37 °C and positioned in a stereotactic frame with a cervical bend of about 30°. Once in place, the tip of an elongated glass micropipette filled with the homologous arterial blood taken from carotid artery of another mouse of the same age and gender (C57Bl/6J) was positioned at a right angle in contact with the atlanto-occipital membrane by means of a micromanipulator. Then 60 µL of blood was injected in the cisterna magna followed by a 30° downward tilt of the animal for 2 minutes. The second infusion of 30 µL of blood into the cisterna magna was performed 24 h after the first one. The individual follow-up of each animal is carried out daily (careful evaluation of weight and well-being). This procedure allows a predictable and highly reproducible distribution of blood, likely accompanied by intracranial pressure elevation that can be mimicked by an equivalent injection of an artificial cerebral spinal fluid (CSF), and represents an acute to mild-model of SAH inducing low mortality.

Introduction

Subarachnoid hemorrhage (SAH) accounts for up to 5% of all stroke cases and constitutes a relatively common pathology with an incidence of 7.2 to 9 patients per 100,000 per year, with a mortality rate of 20%-60% depending on the study^1,2,3. In the acute phase, the mortality is attributable to the severity of bleeding, rebleeding, cerebral vasospasm (CVS) and/or medical complications⁴. In survivors, early brain injury (EBI) is associated with parenchymal extension of hemorrhage and abrupt increase in intracranial pressure, which may result in primary ce....

Protocol

All procedures were performed under the supervision of H. Castel in accordance with the French Ethical Committee and guidelines of European Parliament Directive 2010/63/EU and the Council for the Protection of Animals Used for Scientific Purposes. This project was approved by the local CENOMEXA and the national ethic committees on animal research and testing. Male C57Bl/6J Rj mice (Janvier), aged 8–12 weeks, were housed under controlled standard environmental conditions: 22 °C ± 1 °C, 12 hours/12 hours light/dark cycle, and water and food available ad libitum.

1. Setup of SAH surgery and preparation for injection<....

Results

Experimental timeline, procedure, follow-up and mortality
Figure 1A and Figure 1B summarize the SAH model protocol by double intracisternal injection of blood. Briefly, on the first day of SAH induction (D-1), 60 µL of blood withdrawn from a homologous mouse or 60 µL of artificial cerebrospinal fluid (aCSF) were injected into the cisterna magna in SAH or sham conditions, respectively. The next day (D0), 30 µL of blood withdrawn from a homolo.......

Discussion

Despite the intensity of the research in the field of SAH and the development of therapeutic strategies such as endovascular and pharmacological treatment options increasing over the past twenty years, mortality remains high within the first week of hospital admission and reaches about 50% during the following 6 months^24,25. This current preclinical model by daily double injection of homologous arterial blood into the cisterna magna has been reco.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
absorbable hemostat	Ethicon	Surgicel
absorbable suturing thread	Ethicon	Vicryl 5.0
auto-regulated electric blanket	Harvard Apparatus	50-7087-F
bluetack for capillary fixation	UHU	Patafix
electronic balance	Denver Instrument	MXX-2001
glass capillaries	Harvard Apparatus	GC150F-15	inner diameter 0.86 mm outer diameter 1.5 mm
isoflurane vaporizer	Phymep	V100
micropipette puller	Sutter Instrument Company	P-97
needle 26 G	BD microbalance	300300
non absorbable suturing thread	Peters surgical	Filapeau 4.0
stereotaxic frame	David Kopf instruments	Model 902
surgical equipment	Kent scientific	clamp, microscissors, thin scissors
syringe 20 mL TERUMO	Thermofisher	11866071