Quantitative morphometry of granular 'dot-like' ubiquitin-immunoreactivity in the crus cerebri in asphyxiation and fire fatalities

In the central nervous system (CNS), a variety of ubiquitinated structures have been reported, usually as pathological alterations of the brain related to degenerative diseases or aging. However, previous studies showed an increase in the ubiquitin (Ub)-immunoreactive intranuclear inclusion of the pigmented neurons of the substantia nigra in the midbrain in asphyxiation and fire fatalities in the adult subjects. The aim of the present study was to examine granular 'dot-like' Ub-immunoreactivity in the crus cerebri (cortico-spinal tracts) in related fatalities (over 35 years of age, n=169), including fatal asphyxiation (n=27), drownings (n=14), fire fatalities (n=60), and control groups (n=68). Dot-like Ub-immunoreactivity was clearly observed in the descending tract of the crus cerebri. Morphometric analysis of the positive granular area (dot-like Ub-area) showed a higher value in strangulation and fire fatalities and a lower value in hemorrhagic and head injury deaths, as was observed for the inclusion-type neuronal Ub-positivity. However, there was a difference between those markers: a low value was seen for the inclusion-type neuronal Ub-positivity in hanging and drownings, and a difference in the dot-like Ub-area was detected between fire fatalities with lower and higher COHb levels. Our findings suggested the possible usefulness of these markers for examination of CNS stress responses in traumas, at least in middle-aged and elderly victims and a partial difference in stress reaction between the cortico-spinal tracts and dopaminergic neurons.