[Immunohistochemical distribution of single-stranded DNA in the brain in medico-legal autopsy cases of carbon monoxide intoxication].

To evaluate apoptotic neuronal damage by carbon monoxide (CO) in medico-legal autopsy cases, we investigated the immunohistochemical distribution of single-stranded DNA (ssDNA) as a marker of apoptosis and programmed cell death in the brain. Formalin-fixed paraffin-embedded brain tissue specimens, including cerebral cortex of frontal lobe, substantia nigra of the midbrain and pallidum, from medico-legal autopsy cases of fire fatality (n=63), including cases with blood carboxyhemoglobin (COHb) of a lower (<60%) and a higher (>60%) level (n = 39 and 24, respectively), and CO intoxication without burns (n = 6) were examined, in comparison with acute ischemic heart disease (IHD, n = 29) and asphyxiation due to strangulation (AS, n= 14). In the pallidum, neuronal immunopositivity for ssDNA was significantly higher in fire fatality with a higher COHb level than in IHD (p<0.0001), and CO intoxication cases showed significantly higher positivity than other groups excluding fire fatality with a higher COHb level (p< 0.05). In cases without cardiopulmonary resuscitation, ssDNA-positivity in the pallidum mildly correlated to COHb concentrations (r = 0.31, p<0.05), and the positivity was significantly higher in higher COHb (>60%) cases than in lower COHb (<30%) cases. In the cerebral cortex and substantia nigra of the midbrain, neuronal ssDNA-positivity showed no significant findings with regard to the cause of death and COHb concentration. These findings suggest that CO causes selective neuronal damage in the pallidum.