Ubiquitin immunoreactivity in the midbrain as a marker of stress to motor nervous systems in fatal injury

Previous studies showed an increase in the ubiquitin (Ub)-immunoreactive structures in the midbrain in acute deaths from asphyxiation and in fires in adult subjects. The present study examined the Ub-immunoreactivity in the midbrain as a marker of stress to motor nervous systems in fatal injury cases (over 35 years of age, n=140: blunt injuries, n=82; sharp injuries, n=58), compared with that in control groups (n=61) including death by strangulation, acute cardiac and cerebrovascular diseases. The intranuclear Ub-immunopositive inclusion of the pigmented dopaminergic neurons of the substantia nigra (inclusion Ub-index) and the granular 'dot-like' Ub-immunoreactivity area ('dot-like' Ub-area) in the crus cerebri were analyzed. In blunt injuries, those markers were high in abdomen and back injuries and low in head and chest injuries. The inclusion Ub-index was higher in the crush/pressure injury group than in those with injuries due to impact traffic accidents and falls. 'Dot-like' Ub-area was also low in falls. In sharp injury cases, cardiac injury with hemopericardium showed a higher inclusion Ub-index. These findings suggested that the stress to the motor nervous system may be very intense in crush/pressure injury and hemopericardium than in impact injury and fatal hemorrhages, respectively, and in abdomen and back injuries than in head and chest injuries.