Immunohistochemical and molecular study for differential diagnosis between freshwater and saltwater drowning.

The postmortem identification of drowning in the field of forensic medicine is difficult due to unspecific autopsy findings, and usually, it is a "diagnosis of exclusion". A model of drowning in salt and fresh water was established to discuss the postmortem changes after drowning and the differences between saltwater drowning (SWD) and freshwater drowning (FWD). The organs (brain and 'lung) of 30 rats were extracted at three-time points (0 h, 24 h, and 48 h) after drowning. The histopathological, immunohistochemical,l, and molecular changes in the lung and brain of rats at different time points were investigated. Results show no significant difference in pathological findings between fresh and saltwater drowning. Casp3, JNK, and ERK all showed a rise in their postmortem expression in a time-dependent way; the expression of these three genes is much greater in cases of saltwater drowning compared to cases of freshwater drowning. So, it is concluded that after 24 h and 48 h from death, potent cellular oxidative stress occurred and caused the upregulation of the studied genes.