Functional assessments in mice and rats after focal stroke

Abstract

This paper presents a comprehensive assessment of sensorimotor deficits in the mouse after focal ischaemia induced by occlusion of the middle cerebral artery. Twenty four hours after induction of middle cerebral artery occlusion, mice showed deficits in a range of sensory and motor tasks as assessed by the SHIRPA protocol. In addition they exhibited a decrease in rotarod performance and locomotor activity. Some behaviours, such as locomotor activity, were also impaired in sham operated animals compared to normal controls, although these impairments were not as marked as those exhibited by the ischaemic mice. This is the first comprehensive analysis of the short term effects of permanent focal ischaemia in mice. In a second series of experiments in the rat, rates of recovery over time were examined. Simple (neurological grades, rotarod) and complex (sticky label test) tasks were examined in rats after middle cerebral artery occlusion up to 7 days post-ischaemia. Ischaemic rats had a profound deficit in contralateral performance on the sticky label task with no evidence of recovery. A less marked deficit was also observed in ipsilateral performance of this task. These deficits were still present 7 days after ischaemia. Ischaemic rats also exhibited a deficit on rotarod performance but this had recovered 7 days post-ischaemia. Thus different sensorimotor tasks have different rates of recovery after focal cerebral ischaemia in the rat. Further characterisation of these tasks will enhance their utility meaningful preclinical means of assessing functional recovery of the administration of potential neuroprotective and regenerative therapies.