Long-term assessment of motor and cognitive behaviours in the intraluminal perforation model of subarachnoid hemorrhage in rats

Abstract

The endovascular perforation model of subarachnoid hemorrhage (SAH) is a commonly used model in rats as it is performed without a craniotomy and accurately mimics the physiological effects of SAH in humans. The long-term behavioural profile of the model, however, has not been characterized. Given that humans often have cognitive deficits following SAH, we set out to characterize the behavioural profile as well as the spontaneous temperature changes of rats following intraluminal perforation. Rats were pre-trained on three motor tasks (tapered beam, limb-use asymmetry and the horizontal ladder tasks) prior to receiving a SAH. The animals were then assessed on post-surgical days 3, 7, 14 and 21 on these tasks. At the completion of motor testing, the rats were assessed on a moving platform version of the Morris water task. Despite significant mortality (33%), SAH did not result in lasting motor deficits on any of the tasks examined. However, the SAH group did show a minor cognitive impairment in the Morris water task. In addition, SAH produced a slight, but significant elevation in body temperature (vs. sham operated rats) despite an acute decrease in general home cage activity. The majority of the animals did not have any observable infarcts and the SAH did not significantly affect cortical thickness. In summary, the endovascular perforation model of SAH results in no lasting motor deficits and only minor cognitive impairment in survivors, which alone would be difficult to evaluate in neuroprotection or rehabilitation studies.