Neuronal damage in pericontusional edema zone

In this study, we investigated the molecular biological and histopathological aspects of the etiological mechanisms for pericontusional edema zone (PEZ). The subjects were 5 patients with traumatic brain injury who underwent surgery to evacuate the resulting hematoma. The average age of the subjects was 52 +/- 27.5 years. The GCS at the time of admission was 5-9. At operation apart from evacuating the hematoma, the PEZ was also excised and then examined histopathologically. Cerebrospinal fluid (CSF) levels of IL-6, IL-8, and IL-10 were measured at the time of admission and at 24 and 72 hours. Histological examination revealed large numbers of neutrophils accumulating within blood vessels in the PEZ, with some focal migration. IL-6: CSF levels at the time of admission and at 24, 72, and 72 hours were 550, 4350, and 878000 pg/ml, respectively (median values). IL-8: CSF levels were 715, 804, and 24900 pg/ml, respectively. IL-10: CSF levels were 15, 4, and 5 pg/ml, respectively. High levels of IL-6 and IL-8 were seen from an early stage, and became markedly higher with enlargement of the PEZ. The PEZ is thought to be due to microvascular disturbance by neutrophils stimulated by inflammatory cytokines, and neuronal damage from migrated neutrophils.