Assessment of the relationship between ischemic damage and brain swelling in frozen brain slices

The purpose of the study was to verify a method for the measurement of both cerebral infarction and brain swelling in frozen brain slices for histology. The animals were divided into two groups sham-operated control (n = 10) and focal cerebral ischemia group (n = 10). Focal cerebral ischemia was produced by permanent occlusion of the left middle cerebral artery. The rats were sacrificed 24 hours postocclusion. The brain was divided into two through the corpus callosum. Each hemisphere was weighted and frozen. Cerebral infarction and brain swelling were each assessed at 8 predetermined coronal planes. The volume of brain swelling was obtained by subtracting the total volume of nonischemic hemisphere from the total volume of the ischemic one. In the MCA occlusion group, brain infarction and the differences of hemispheric volume and weight between the right and left hemispheres were consistently observed, whereas sham-operated rats demonstrated no brain infarction or significant differences between two hemispheres. There were good corelationships not only between the volumes of brain edema and infarction (p < 0.05) but between the volume of brain edema and the difference in weight (p < 0.01) also. The results indicate that the measurement of the volume of ischemic brain edema in frozen brain slices may be useful in elusidating relationship with ischemic brain damage.