PHOTOCHEMICALLY-INDUCED VASCULAR DAMAGE IN BRAIN CORTEX - TRANSMISSION AND SCANNING ELECTRON-MICROSCOPY STUDY

Morphological changes of microvessels of cerebral cortex were evaluate d in a model of cerebral infarction initiated by a photochemical react ion. Rats were treated with intravenous injection of rose Bengal and i rradiated from a halogen lamp source through an intact cranium to prec ipitate microvascular damage. Investigations in transmission and scann ing electron microscopy revealed platelet aggregation on endothelial c ells preceded by its early ultrastructural damage. Other typical micro scopic features of brain ischaemic injury were present suggesting that the present method may be used as a model for investigating ischemic brain damage. Since the photochemical activation of the rose Bengal dy e results in formation of reactive oxygen species this model may be pa rticularly useful to elucidate the role of free radical-mediated endot helial damage in the formation of microthrombi and blood-brain-barrier integrity.