Brain oedema in experimental closed head injury in the rat.

Development of brain oedema was studied in a new closed head injury (CHI) model of the rat. This acceleration impact models does not produce the dramatic blood pressure surge seen with fluid percussion injury. Sixteen Sprague Dawley rats were separated into 4 groups; 8 survivors sacrified at 4 and 24 hours post injury; and 8 Sham treated animals sacrified at the same time intervals. Brains were analyzed using gravimetric technique. Despite absence of the high post traumatic blood pressure surge, mild oedema was observed in 4 of 5 slices at 4 hours post injury. At 24 hours post injury, significant oedema was observed throughout the brain tissue. The study demonstrates that traumatic oedema develops following acceleration impact within a 24 hour period of CHI. The oedema occurs in the absence of significant brain stem damage and blood pressure rise characteristic of this new CHI model.