Early postmortem biochemical and histopathological changes in the kidney, liver, and muscles of dogs

The goal of the present study was to investigate the biochemical and histological changes in dog’s kidney, liver, heart, and skeletal muscles within 72 h after death. Ten male mongrel dogs aged from 1 to 2 years old were subjected to this study. Dogs were euthanized by the rapid intravenous injection of a lethal dose of sodium thiopental, and then the liver, kidney, heart, and skeletal muscle samples were collected from the whole carcasses at different time intervals 4, 12, 24, 48, and 72 h postmortem. Samples were divided into two parts; one part was used for measuring tissue levels of lactate dehydrogenase (LDH), lactate, creatine phosphokinase (CPK), and aspartate aminotransferase (AST). The other part was subjected to histopathological examinations. On the biochemical level, LDH in the liver, kidney, and cardiac and skeletal muscles showed a significant increase at 4 h followed by significant decrease at 48 and 72 h in all the studied tissues. Lactate level showed variable degrees of increase and decrease in kidney and liver tissues while muscles showed increased lactate concentration during the first 48 h then decreased at 72 h. CPK in cardiac and skeletal muscles showed similar changes; it increased from 4 to 48 h then decreased at 72 h. AST level decreased in liver tissue at 4 until 72 h, while in muscular tissue it showed a delayed reduction in concentration which started at 12 and 24 h in the cardiac and skeletal muscles respectively. Similar changes of AST levels in both skeletal and cardiac muscles were observed; it increased at 4 h and then decreased at 24, 48, and 72 h. Histopathological changes in the kidneys were the earliest changes seen in tissue. The changes in the hepatic tissue were earlier than those of heart and skeletal muscle. We concluded that LDH enzyme showed regular changes in all examined tissues; the biochemical changes in cardiac and skeletal muscles were regular and can be useful in estimation of the time of death. The histopathological changes in the kidney, liver, and cardiac and skeletal muscles were very clear and can be used for estimating the postmortem intervals in dogs.