Possibility of determining injury duration based on changes in histomorphometric characteristics of the thymus

Background: Lymphoid tissue is the first to react to stress, which manifests as characteristic morphological manifestations, based on which it is possible to study the duration of damage. Aims: Study of the dynamics of changes in the histomorphometric characteristics of the rat thymus during regeneration of the musculocutaneous tissue during mechanical thigh trauma. Material and methods: In total, 84 sexually mature rats were enrolled. These were divided into two groups (experiment and control), which were further classified into four subgroups depending on the time elapsed since the injury (1, 3, 15, and 25 days). Mechanical damage was simulated using a setup that transferred kinetic energy (comparable to a 5.6-mm rifle bullet) to tissues. Subsequently, the animals were removed from the experiment by decapitation; their thymus was removed and microscopically examined. In arbitrary units, the total area of the lobules as well as the area of the cortical and cerebral zones was determined. Results: Our research results indicate different phases of changes in the histomorphometric characteristics of the thymus, which correspond to the course of the wound and can be used in forensic practice to determine the duration of the injury. Conclusions: Mechanical trauma, considered as a stress reaction, causes involutive changes in the thymus and is characterized by changes in the area of the thymus cortex and medulla as well as regular dynamics of changes in the thymic lobules at different stages of wound regeneration.