Closed head injury in rats: histopathological aspects in an experimental weight drop model.

PURPOSE To study histopathological findings due to a model of closed head injury by weight loss in rats. METHODS A platform was used to induce closed cranial lesion controlled by weight loss with a known and predefined energy. 25 male Wistar rats (Rattus novergicus albinus) were divided in five equal groups which received different cranial impact energy levels: G1, G2, G3 and G4 with 0.234J, 0.5J, 0.762J and 1J respectively and G5 (Sham). Under the effect of analgesia, the brain of each group was collected and prepared for histopathological analysis by conventional optic microscopy. RESULTS It was observed greater number of injured neurons in animals of group 4, however neuronal death also could be noticed in animals of group 5. Intraparenchymal hemorrhages were more frequent in animals of group 4 and the cytotoxic brain swelling and vascular congestion were more intense in this group CONCLUSION The histopathological analysis of these findings allowed to observe typical cranial trauma alterations and these keep close relation with impact energy.