Several nuclei in brain stem are well known to play an important role in supporting human life. However, the connection between neural changes of brain stem and the cause of death is not yet fully understood. To investigate the correlation of brain stem damage with various cause of respiratory disorders, neural changes of the arcuate nucleus (
ARC), the hypoglossal nucleus (HN) and the inferior olivary nucleus (IO) were examined using immunohistochemical technique. Based on the cause of death, the forensic autopsy cases were divided into 5 groups as follows. Group I: hanging,
ligature strangulation and manual strangulation, Group II: smothering and
choking, Group III:
drowning, Group IV:
respiratory failure, control group:
heat stroke and
sun stroke. Brain was fixed with
phosphate-
buffer formalin, and the brain stem was horizontally dissected at the level of apex, then embedded in
paraffin. The sections were stained with the
antibodies against
microtubule-associated protein 2 (MAP2), muscalinic
acetylcholine receptor (mAChR), c-fos gene product (c-Fos) and 72 kD
heat-shock protein (HSP70). Three nuclei showed no obvious morphological changes in all examined groups. However, in case of
asphyxia (Group I to III), neurons in HN were positively stained with both HSP70 and c-Fos
antibodies. This may indicate that the occlusion of upper airway results in the neuronal damage of HN without their morphological changes. Positive staining of HSP70 and c-Fos in IO was more frequently observed in Group III than other 4 groups. Since IO is involved in maintaining body balance which is often disturbed by
drowning, it seems possible that neuronal damage in IO observed in
drowning may be related to the disturbance of body balance. These observations indicate that immunohistochemical study on the damage to neurons in brain stem nuclei can provide useful information for determining the cause of death.