Basic Neuroscience
A new percutaneous model of Subarachnoid Haemorrhage in rats

https://doi.org/10.1016/j.jneumeth.2012.08.010Get rights and content

Abstract

Objective

Describe the results obtained with a new percutaneous, intracisternal model of Subarachnoid Haemorrhage (SAH) in Wistar rats by a single injection of non-heparinised, autologous blood.

Methods

Once anaesthetized the rat was fixed prone in a stereotaxic frame. After identifying the projection of the occipital bone, the needle of the stereotaxic frame aspirated towards the foramen magnum until it punctured through the atlanto-occipital membrane and obtained cerebrospinal fluid. Autologous blood (100 μl) was withdrawn from the tail and injected intracisternally. This procedure was repeated in the sham group, injecting 100 μl of isotonic saline. On the fifth day post-intervention, the rats were anaesthetized and the brain was exposed. After a lethal injection of ketamine the brain was explanted and fixed in paraformaldehyde. Gross and microscopic inspection of the slices revealed the existence or non-existence of pathological findings.

Results

A total of 26 rats were operated on (13 in the SAH group/13 in the sham group). The average time between obtaining the blood and the start of the intracisternal injection was 10 (±1.2) s. The mortality rate was 16.12%. Intra- and extraparenchymal ischemic–haemorrhagic lesions were found in three animals (23.07%) – all from the SAH group – with ischemic neuronal cell injury detected in two of the three.

Conclusions

The new murine model of SAH is easy to perform, with low mortality, minimally invasive, which makes it interesting for future studies on vasospasm-related delayed SAH complications.

Highlights

► We described a new rat model of SAH by percutaneous injection of autologous, non-heparinised blood into the intracisternal space. ► The model is reproducible, easy-to-perform and quick. ► The model presents low mortality rates and subsequent ischemic–haemorrhagic lesions.

Introduction

Patients with Spontaneous Subarachnoid Haemorrhage (SAH) have a high mortality rate within thirty days. This elevated level shows a slight tendency to descend, which is possibly related to the new diagnostic techniques and treatment (Sandvei et al., 2011). Although some clinical factors exist which improve prognosis by means of suitable intervention, a high percentage of the variables are non-modifiable (Andaluz and Zuccarello, 2008, Goldacre et al., 2008, Muñoz-Sánchez et al., 2009). Vasospasm secondary to SAH is the leading cause of sequelae following a ruptured aneurysm in the cerebral arteries (Dorsch, 2002). After day four, 30% of patients go on to develop symptomatic vasospasm (SV) (Vergouwen, 2011). At present our understanding of the pathophysiological events that occur after SAH is insufficient and this leads to two crucial facts: firstly, we do not have reliable tools to unmistakeably select the patients who are at risk for SV, and secondly, with the exception of nimodipine, there is no existing therapy to avoid or solve this complication. This leads to variability in the clinical management of patients worldwide (Stevens et al., 2009). For these reasons we must promote new lines of research that facilitate pathophysiological understanding of the phenomena associated with vasospasm after SAH, and test treatments that may induce changes in the mortality rates and in the number of disabling sequelae (Laskowitz and Kolls, 2010).

Despite the large number of species (rats, rabbits, dogs, etc.) used to conduct studies about vasospasms after SAH, rat models of SAH are quite widespread. This is due to the ease in handling, housing and cost (Megyesi et al., 2000). Since the studies by Barry et al. in 1979, multiple invasive models have been generated with large differences between them, without achieving the optimal model (Barry et al., 1979). We have aimed to produce a rat model of SAH that meets all the characteristics of an ideal experimental model: simple to perform, minimally invasive, efficient and that accurately reproduces the natural development of the disease.

Section snippets

Methods

The procedures were performed in the experimental operating room of the Seville Biomedicine Institute (Instituto de Biomedicina de Seville [IBiS]), Virgen del Rocío University Hospital, Seville, Spain. This research project was overseen and approved by our hospital's Animal Experimentation Committee. It met all ethical standards for research and legal requirements as established by the corresponding legislation (Directive 2010/63/EU).

Wistar rats (300–350 g) were used as the model. The procedure

Results

A total of 30 animals were operated on following the schema of the percutaneous intracisternal injection model.

Preliminary, we performed the procedure on four rats. We used the same system in terms of positioning the animal and location of the cisterna magna, except that instead of injecting fresh blood or physiological saline, we injected a volume of 100 μl methylene blue. The subsequent extraction of the brain showed that the dye had followed a proper distribution throughout the subarachnoid

Discussion

We present a new rat model of SAH which is simple to perform, minimally invasive, quick and with low mortality.

In literature there currently exist many rat models of SAH. These may be separated into three groups: the external vessel puncture under direct vision (Barry et al., 1979, Kader et al., 1990), the endovascular filament puncture (Veelken et al., 1995), and intracisternal injection through surgical procedures (Delgado et al., 1985, Solomon et al., 1985, Bederson et al., 1995).

The first

Conclusion

This paper details a new rat model of SAH by percutaneous injection of autologous, non-heparinised blood into the intracisternal space. This is a model which is reproducible, easy-to-perform, quick and it presents low mortality rates. This makes it very interesting for future studies on the delayed vasospasm complications of SAH.

Conflict of interest

The authors have no conflict of interests.

Acknowledgement

This study has been funded by Health Research Fund 2010 (Fondos de Investigación Sanitaria, FIS 2010) from the Instituto de Salud Carlos III, Spain.

References (34)

  • T.J. Delgado et al.

    Subarachnoid haemorrhage in the rat: angiography and fluorescence microscopy of the major cerebral arteries

    Stroke

    (1985)
  • T.J. Delgado et al.

    Subarachnoid hemorrhage in the rat: cerebral blood flow and glucose metabolism after selective lesions of the catecholamine systems in the brainstem

    J Cereb Blood Flow Metab

    (1986)
  • N.W. Dorsch

    Therapeutic approaches to vasospasm in subarachnoid hemorrhage

    Curr Opin Crit Care

    (2002)
  • J.R. Dusick et al.

    A minimally-invasive rat model of subarachnoid hemorrhage and delayed ischemic injury

    Surg Neurol Int

    (2011)
  • L. Edvinsson et al.

    Involvement of perivascular sensory fibres in the pathophysiology of cerebral vasospasm following subarachnoid hemorrhage

    J Cereb Blood Flow Metab

    (1990)
  • P. Gaetani et al.

    High-dose methylprednisolone and ‘ex vivo’ release of eicosanoids after experimental subarachnoid haemorrhage

    Neurol Res

    (1990)
  • M.J. Goldacre et al.

    Mortality rates for stroke in England from 1979 to 2004: trends, diagnostic precision, and artifacts

    Stroke

    (2008)
  • Cited by (0)

    View full text