Distal middle cerebral artery occlusion does not result in depression-like behaviours

Background: Stroke is a devastating neurological injury, which can result in significant cognitive and behavioural deficits. Modelling the disease processes associated with stroke in animals is key to the development of novel therapeutic approaches. However, some aspects of stroke pathophysiology, including neuropsychiatric symptoms, do not translate well from humans to animals. Here, we aimed to investigate the development of post-stroke depression in a rodent model of stroke. Methods: The distal middle cerebral artery (MCA) was permanently occluded by electrocoagulation in adult male C57/Bl6/J mice. Animals were allowed to survive for 6 hours, 24 hours, 2 days, 5 days or 7 days prior to behavioural testing. Brains were taken to confirm lesion volumes at the above times. Behavioural tests studied basic exploration and motivation (open field and marble burying) as well as depression-like behaviours (tail suspension and sucrose preference). Results: Animals developed robust and reproducible lesions in the cortex but whilst stroke reduced activity in the open field, animals showed no associated behavioural deficits in any of the tests used for depression-like behaviours. Conclusions: The distal middle cerebral artery occlusion (MCAO) model results in a small cortical lesion which produces no depression-like behaviours. These negative data are important for those wishing to investigate the more cognitive and behavioural aspects of stroke.