Experimental penetrating head injury: some aspects of light microscopical and ultrastructural abnormalities

A high velocity model of penetrating head injury has been developed in the rhesus monkey and a lower velocity model in the baboon. It is apparent that pathological changes are widespread and develop early although the pathogenesis of the diffuse vascular changes is unknown. The present study involved the sampling of grey and white matter from 20 monkeys with high velocity injury, and 10 baboons with low velocity injury together with similar material from a number of normal control animals. 30 minutes after a high velocity injury swelling of perivascular astrocytes was present, sometimes associated with an increase in extracellular fluid. Animals with lower velocity injuries survived for some hours. Astrocytic swelling and perivascular oedema associated with cellular necrosis was frequently found in this group. The pathogenesis of these lesions is discussed.