Expression times for hsp27 and hsp70 as an indicator of thermal stress during death due to fire.

The expression of heat shock proteins (hsps) increases in cases of hyperthermal cellular stress in order to protect cellular structures. Hsps can be visualized with immunohistochemical staining. We examined 48 cases of death from fire and excessive heat and a control group of 100 deaths without any perimortem thermal stress, measuring both the hsp27 and hsp70 expressions in myocardial, pulmonary, and renal tissues. The results revealed a correlation between hsp expression and survival time. Hsps are expressed rapidly within seconds or minutes after exposure to heat stress. In particular, hsp27 is expressed fast in high levels, whereas hsp70 expression is higher in the pulmonary and renal tissue of long-term survivors. In the myocardial tissue, hsp27 expression dominated in both short- and long-term survival. The expression pattern is strongly dependent on the organ structure and the survival time, which should be considered in future postmortem studies on hsps.