IMMUNOHISTOCHEMICAL INVESTIGATION OF HYPOXIC-ISCHEMIC BRAIN-DAMAGE INFORENSIC AUTOPSY CASES

A neuropathological study of 41 forensic autopsy cases of hypoxic/isch emic brain damage has been undertaken, using immunohistochemical stain ing to detect the 70-kDa heat shock protein (hsp70) and the status of the glial cells. In cases surviving 2-5 h after hypoxic/ischemic injur y, ischemic cell changes were seen whereas glial reactions were not ap parent. In cases of longer survival, neuronal necrosis and a loss of n eurons were seen, and these changes were accompanied by proliferation of glial fibrillary acidic protein (GFAP), vimentin-positive astrocyte s and microglia which transformed into rod cells or lipid-laden macrop hages. In cases with a history of hypoxic attacks, GFAP-positive and v imentin-negative astrocytes had proliferated in the CA3 and CA4 region s of hippocampus. The cases of severe hypoxic injury, such as an asthm atic attack and choking, showed no ischemic changes in the hippocampal neurons. On the other hand, the CA1 pyramidal cells showed neuronal n ecrosis in a patient suffering from tetralogy of Fallot (TOF), who sur vived for 2 h after a traffic accident. Therefore, it is suggested tha t even moderate hypoxic injury induces astrocytosis in the CA3 and CA4 regions and may affect the neuronal proteins and the metabolism, and that in cases with a history of hypoxic attacks neuronal damage may be severe even several hours after ischemic injury. The protein hsp70 ex pression was found in the CA2, CA3 and CA4 regions in cases of long-te rm survival after severe hypoxic/ischemic injury and in cases of alcoh olic intake or toluene abuse just before acute death. Thus, it is sugg ested that the detection of hsp70 in the hippocampus indicates hypoxic /ischemic injury or other stress prior to death. In forensic practice, immunohistochemical investigation of the hsp70 and glial cell stainin g can be of great value for diagnosing not only hypoxic/ischemic brain damage during the process of death but also the victim's past history of hypoxic attacks.