Infarct Volume, Edema and Neurological Score in a Transient Focal Ischemic Rat Stroke Model

Background and Purposes:Survivors of a stroke manifest abrupt development of a neurological deficit. Middle cerebral artery(MCA)occlusion is a widely used experimental model of ischemic stroke. The purposes of the present study were to investigate the effect of recovery time(24 hours versus 14 days)on infarct volume, brain edema and neurological deficits by using the transient rat MCA ischemia model. Methods:Twenty-four young male Sprague-Dawley rats were undergone MCA occlusion procedure for 60 minutes under an operating microscope. Twelve rats were killed 24hours and 12 rats were killed 14 days after the MCA ischemic procedure. The infarct volume, edema and neurological score were measured for comparison between the two groups. Reults: The mean infarct volume measured 24 hours post ischemic procedure was 17.52%±10.97% of total volume of the ipsilateral hemisphere, and was 11.19%±5.38% when measured at killing 14 days post ischemic procedure (t=-1.79 , P=.1049). A significant reduction (P=.0306)in edema had also been noted in rats after 14 days of recovery (3.14%±4.60%)compared to that after 24 hours of recovery(7.98%±5.20%).Conclusion:The decrease of infarct volume at 14 days after the ischemic insult, suggested a resolution of brain edema and possible loss of brain tissue. In conclusion, the present study demonstrated that infarct volume and edema were time dependent. Major advantages of the model used in the study were a 100% incidence of infarction and the availability and low cost of rats. Because the model is reproducible, the effects of various therapeutic agents on neurological outcome and size of infarction produced by focal cerebral ischemia can be studied in the future.