The Rabbit Blood-shunt Model for the Study of Acute and Late Sequelae of Subarachnoid Hemorrhage: Technical Aspects

Summary

The experimental intracranial pressure-controlled blood shunt subarachnoid hemorrhage (SAH) model in the rabbit combines the standard procedures — subclavian artery cannulation and transcutaneous cisterna magna puncture, which enables close mimicking of human pathophysiological conditions after SAH. We present step-by-step instructions and discuss key surgical points for successful experimental SAH creation.

Abstract

Early brain injury and delayed cerebral vasospasm both contribute to unfavorable outcomes after subarachnoid hemorrhage (SAH). Reproducible and controllable animal models that simulate both conditions are presently uncommon. Therefore, new models are needed in order to mimic human pathophysiological conditions resulting from SAH.

This report describes the technical nuances of a rabbit blood-shunt SAH model that enables control of intracerebral pressure (ICP). An extracorporeal shunt is placed between the arterial system and the subarachnoid space, which enables examiner-independent SAH in a closed cranium. Step-by-step procedural instructions and necessary equipment are described, as well as technical considerations to produce the model with minimal mortality and morbidity. Important details required for successful surgical creation of this robust, simple and consistent ICP-controlled SAH rabbit model are described.

Introduction

Aneurysmal subarachnoid hemorrhage (SAH) is one of the most life threatening neuropathological conditions, frequently leading to permanent neurological damage or death¹. Past research has focused on delayed cerebral vasospasm (DCVS) as the primary etiology of neurological deficits associated with SAH². However, the generally poor clinical outcomes of patients suffering from SAH after treatment of vasospasm has led to an expansion of the research focus to include the effects of early brain injury (EBI) after SAH³. Greater understanding of the significance of both EBI and DCVS in contributing to poor clinical outcomes after SAH is essent....

Protocol

Three month old female New Zealand rabbits weighing 2.5 – 3.5 kg were used for this procedure. The study was performed in accordance with the National Institutes of Health guidelines for the care and use of experimental animals and with the approval of the Animal Care Committee of the Canton of Bern, Switzerland (approval #105/13). All surgical procedures were performed under sterile conditions at the Experimental Surgical Institute of the Department of Clinical Research at Bern University Hospital in Bern, Switzerland. A veterinary anesthesiologist monitored the animals during surgery and throughout recovery.

1. Animal Preparation, Pos....

Results

The rabbit blood shunt model of SAH described in this report produces EBI in the hippocampus (Figure 2A, B), basal cortex (Figure 2A, B), and cerebral vasculature (Figure 2C) as early as 24 hr after injury and shows a characteristic blood distribution (Figure 2D)⁸. In addition, the model triggers moderate to severe degrees of DCVS on day three after SAH induction (Figure 3)¹⁰. The mortality rate is .......

Discussion

The shunt model produces pathology similar to that observed in humans after acute SAH^3,8,10. It has been suggested that EBI may exacerbate, maintain and even trigger DCVS¹², and as such this model may aid in investigating both the early and late DCVS phases, including EBI and DCVS interactions following SAH. In particular, repeatable in vivo DCVS monitoring techniques including DSA¹³, computed tomography angiography¹⁴, and transcranial Doppler¹⁵ are more rea.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Equipment
Operation microscope	Zeiss, Jena, Germany		Zeiss, OPMI-MD surgical microscope
Surgical equipment	B. Braun, Germany		Forceps medical no. 5; vessel scissors 8 cm; microclip 4 mm
Respirator	Hugo Sachs
Hair clipper	3M Surgical Clipper		Starter Kit 9667A
Body warm plate	FHC
Blood gas analyzer	Radiometer, Copenhagen, Denmark	ABL 725
Cardiac monitoring	Camino Multi-Parameter Monitor, Integra, Plainsboro, NJ, US	AP-05
Software analysis	BIOPAC Systems, Inc., Goleta, CA, USA		Biopac MP100 and acqKnowledge software,version 3.8.1
Software analysis	ImagePro Discovery, MediaCybernetics, Silver Spring, MD, USA		Image-Pro Plus version
Angiography apparatus	DFP 2000 A-Toshiba	MIIXR0001EAA
ICP monitor	Camino Laboratories, San Diego, CA, USA		ICP monitor, Model 110-4B
Blood flow monitor	Oxford Optronix Ltd., Oxford, UK		CAL KIT microsphere solution
Laser-Doppler flowmetry fine needle probes	Oxford Optronix Ltd., Oxford, UK		MNP110XP, 0.48 mm diameter
Pressure tube	B. Braun, Germay		PE 1.0 mm × 2.0 mm
Anesthesia monitor	GE Medical Systems, Switzerland		Datex S5 Monitor
Material
20 G vascular catheter	Smiths Medical		Jelco i.v. catheter, REF 4057
5.5 F three-lumen central venous catheter	Connectors, Tagelswangen, Switzerland		Silicone catheter STH-C040
22 G x 40 mm needle	Emergo Group Inc., Netherlands
High-speed microdrill	Stryker, Solothurn, Switzerland	5400-15
Bone wax	Ethicon, Johnson & Johnson,NJ, USA	ETHW31G
Bipolar forceps	Aesculap, Inc., PA, US	US349SP
Ketamin			Any generic product
Xylazine			Any generic product
Buprenorphine			Any generic product
Fentanyl			Any generic product
Transdermal fentanyl matrix patches			Any generic product
Lidocaine 1%			Any generic product
4% papaverin HCl			Any generic product
Neomycin sulfate	Research Organics Inc., OH, USA		Any generic product
Povidone-iodine			Any generic product
0.9% sodium chloride			Any generic product
Iopamidol	Abott Laboratories, IL, USA		Any generic product
3-0 resorbable suture	Ethicon Inc., USA	VCP824G
5-0 non absorbable suture	Ethicon Inc., USA	8618G
4-0 polyfilament sutures	Ethicon Inc., USA	VCP284G