PHENYTOIN-INDUCED CEREBRAL THROMBOSIS IN RATS - CEREBRAL ULTRASTRUCTURE, WATER-CONTENT AND ISCHEMIC VOLUME IN THE ACUTE-PHASE

A new rat model for multifocal cerebral thrombosis has recently been r eported (Tani et al., 1994; 1995). Ultrastructural changes in the cere bral neocortex in the acute phase were investigated in order to charac terize the early pathological events in this model. A bolus injection of alkaline phenytoin solution (pH 10.8) into one internal carotid art ery in the rat caused severe endothelial injury accompanied by thrombo sis in the cerebral vasculature within 5 minutes, and severe oedema of the ipsilateral hemisphere within an hour. Cerebral water content was measured by the simple dry-wet method, and cerebral surface area and the surface area and volume of the ischaemic zone were measured using computer-aided image analysis. Good correlations were demonstrated bet ween cerebral water content and cerebral surface area, and between the surface area and volume of the ischaemic zone. We report here that qu antitative evaluation of acute cerebral damage induced by phenytoin so lution is possible with high reliability using simple image analysis.