Postmortem Changes in Electrolytes and Adrenal Gland at Different Intervals in Adult Male Rats

The importance of determining time of death is crucial to forensic cases. The ability to use electrolytes, ions and adrenal gland changes to determine the postmortem intervals were examined in this study. A total of 9 rats were used, three rats for determining postmortem “zero hour” the remaining 6 rats were divided equally into two groups to investigate postmortem “six hour” and postmortem “twelve hour”. For each time interval postmortem, the vitreous humor was gently withdrawn for evaluation of Na, Cl and K levels as well as Ca and P. Part of skeletal and cardiac muscles was taken at postmortem 0, 6, and 12 h for lactate analysis. The left adrenal gland was excised and fixed in 10% formalin solution and stained with hematoxylin eosin (H&E) and a special stain for adrenal gland. The volume of the cortex and medulla of the adrenal gland was evaluated. The levels of Na and Cl showed non-significant (P=0.4) changes at 0, 6 and 12 h. The K level was increased significantly (P=0.01) in rats at 0 h compared to 12 h. The Ca was decreased significantly (P=0.02) in rats at 0 h compared to 12h. The lactate in skeletal (P=0.04) and cardiac muscles (P=0.001) showed significant increase at 12 h than that at 0 h. Total volume of the adrenal gland and adrenal cortex has been increased at 12 h, however, significant decrease in medullary volume (P= 0.03) was detected at 12 h. Marked expansion of cortex was detected. The cellular outline of the medulla was indistinct. Pyknotic nuclei were observed in several places at 12 h. In conclusion, K and Ca in vitreous humors as well as lactate levels in skeletal and cardiac muscle tissues were markedly changed by postmortem time intervals. Histopathological changes and the volume of adrenal gland could be used reliably in determining the postmortem intervals. A more detailed study including large number of rats is planned in the near future.