A new model for diffuse brain injury by rotational acceleration: I model, gross appearance, and astrocytosis

Rapid head rotation is a major cause of brain damage in automobile crashes and falls, This report details a new model for rotational acceleration abou t the center of mass of the rabbit head. This allows the study of brain inj ury without translational acceleration of the head. Impact from a pneumatic cylinder was transferred to the skull surface to cause a half-sine peak ac celeration of 2.1 x 10(5) rad/s(2) and 0.96-ms pulse duration. Extensive su barachnoid hemorrhages and small focal bleedings were observed in the brain tissue. A pronounced reactive astrogliosis was found 8-14 days after traum a, both as networks around the focal hemorrhages and more diffusely in seve ral brain regions. Astrocytosis was prominent in the gray matter of the cer ebral cortex, layers II-V, and in the granule cell layer and around the axo ns of the pyramidal neurons in the hippocampus. The nuclei of cranial nerve s, such as the hypoglossal and facial nerves, also showed intense astrocyto sis. The new model allows study of brain injuries from head rotation in the absence of translational influences.