A new percutaneous model of Subarachnoid Haemorrhage in rats

► 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. 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. 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 Autologous blood (100μl) was withdrawn from the tail and injected intracisternally. This procedure was repeated in the sham group, injecting 100μl 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. 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. 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.