Quantitative analysis of single-stranded DNA immunoreactivity as a marker of neuronal apoptosis in hippocampus with regard to the causes of death in medicolegal autopsy

Abstract

The present study immunohistochemically investigated single-stranded DNA (ssDNA) as a marker of DNA injury during apoptosis and programmed cell death to evaluate neuronal damage in the hippocampus with regard to the cause of death in serial medicolegal autopsy cases ( n = 335, <48 h postmortem). Formalin-fixed paraffin-embedded brain tissue specimens were used. Neuronal ssDNA-immunopositivity in CA1 and CA4 regions was independent of the age, gender or postmortem interval, and generally low in acute deaths. Positivity in these regions was moderately correlated in all cases ( r = 0.64, P < 0.001), and marked correlations were detected in drowning ( r = 0.98, P < 0.001) and drug intoxication ( r = 0.86, P < 0.001). In brain injury, survival time-dependency within 48 h was not detected in CA1, but mildly present in CA4 ( r = 0.38, P < 0.01). However, a rapid increase was shown in cerebral contusion and brain stem injury. These findings suggested that the analyses of ssDNA-immunohistochemistry in the hippocampus may be useful for evaluating neuronal damage in various causes of death.