Various stresses can be followed by sudden unexpected deaths, and autopsies sometimes fail to identify pathological findings that determine the cause of death. Pathologists occasionally explain such deaths as being due to overstimulation of sympathoadrenal systems, but postmortem assessment of antemortem sympathoadrenal activity has not been established. An animal model of weight
injuries was used to quantify sympathoadrenal response to
contusion stress, which is common in forensic fields. A weight was dropped from a given height onto the right dorsal limb of each anesthetized rat, with a control group and three stress groups (n = 4, each): 1000 g-80 cm, 1000 g-40 cm, and 500 g-40 cm. To explore the
postmortem changes, we also included ten groups comprised of control and 1000 g-80 cm groups, whose tissues were harvested during 12 hours after
euthanasia. Real-time quantitative polymerase-chain reaction was performed to quantify relative expression levels of mRNAs for
catecholamine biosynthetic
enzymes in the adrenals and the anterocervical ganglia:
tyrosine hydroxylase (TH),
dopamine beta-hydroxylase (DBH) and
phenylethanolamine N-methyltransferase (PNMT). The expression levels of all target mRNAs in the adrenals increased with the intensity of impact (TH, p < 0.0005; DBH and PNMT, p < 0.005), and particularly, TH
mRNA level exhibited near-stepwise elevation (p < 0.05). In contrast, no significant differences were detected in the anterocervical ganglia. Moreover, these
mRNA levels in the adrenals decreased with increasing postmortem interval length. Thus, TH
mRNA level may be a good marker of sympathoadrenal response to
contusion stress during the early postmortem period.