Estimation of the Time Since Death Based on the Post-mortem Histopathological Changes in a Rat Brain: An Observational Study

A comprehensive inference of the structural alterations that occur in the body after death plays a pivotal role in the accurate interpretation of the time since death in many human and animal death investigations. Particular estimation of post-mortem interval (PMI) is usually affected by many frequently changed environmental and other factors that influence the sequential changes that happen to a body after death. Histopathologic investigation in autopsy is a unique technique to investigate PMI. Moreover, it is a supplementary investigation in cases where macroscopic examinations fail to display a diagnostic pathology regarding death. Here, we investigated the post-mortem histopathological changes in rats' brains to pinpoint the time that elapsed since death. For this purpose, we used 72 male Sprague-Dawley rats divided into two main groups 36 young-aged rats and 36 adult-aged rats. The two main groups were subdivided into 6 subgroups (6 rats/subgroup). After accommodation, rats were cervically dislocated and intact brain was collected at 0-hour post-mortem and the at 2nd, 4th, 8th, 12th, and 24th hrs post-mortem at room temperature (RT) and 4oC. The histopathological changes of collected brain tissues revealed that the post-mortem changes begin to be emphasized after 8th hrs post-mortem in both young and adult rats at RT than at 4oC. Those changes included hemorrhage, mild neuronal degeneration, and apoptotic neurons that were prominent in the cerebral cortex. Moreover, cerebral cortex histopathologic changes continued till the 24th hrs post-mortem. Also, the cerebellar changes followed the same path as the cerebral ones. However, the results deduced that the post-mortem changes were prominent at RT in young-aged rats. In conclusion, observation of the histopathological changes of brain tissue under certain individual and environmental circumstances can be an effective, inexpensive, and additional tool to accurately estimate the PMI.