Diffuse axonal injury due to lateral head rotation in a rat model

Object. The authors investigated the ramifications of producing diffuse axonal injury (DAI) by lateral head rotation in a rat model. Methods. Using a special injury-producing device, the rat's head was rapidly rotated 90° in the coronal plane at an angular velocity of at least 753.13 rad/second and an angular acceleration of at least 1.806 × 105 rad/second2; the rotation was complete within 2.09 msec. There were no statistically significant changes in PO2, PCO2, pH, or blood pressure values at 5, 15, or 60 minutes after head rotation compared with their respective preinjury baseline values. The rats exhibited posttraumatic behavior suppression for an average of 12.6 minutes. The mortality rate was 17%. The rats that survived had diffuse subarachnoid hemorrhage around the brainstem and upper cervical cord, but no obvious brain contusion. In sections stained with silver or hematoxylin and eosin, axonal swelling and bulblike protrusions at the axonal axis were observed in the medulla oblongata, midbrain, upp...