Evaluation of Muscle Proteins for Estimating the Post-Mortem Interval in Veterinary Forensic Pathology

SIMPLE SUMMARY: The delimitation of the postmortem interval (PMI) is a very important parameter in veterinary forensic medicine. Indeed, the PMI can provide law enforcement with useful information to correctly determine a temporal relationship between a suspect’s actions and murder or to deny or confirm the testimony of a witness. Unfortunately, postmortem cadaveric changes, which are useful in investigating the PMI, have been poorly investigated in animals. In the present study, we evaluated the postmortem modifications of desmin and dystrophin over time and their correlation with PMI in dogs. To this aim, 10 dead adult dogs were evaluated for 4 days; for each animal, a cube of muscle tissue was collected from the vastus lateralis and triceps brachii. Muscle tissues were removed at 3 h postmortem and every 24 h until 96 h after death. Protein expression levels were analyzed by immunohistochemical examination and immunoblot analysis. The obtained results showed that dystrophin proteins had a higher degradation rate as compared to desmin. Overall, this study identified proteins with different postmortem degradation resistance, providing a reference basis for better investigating PMI in dogs. ABSTRACT: Postmortem cadaveric changes are commonly used to estimate the postmortem interval (PMI) in humans and animals. However, these modifications have been poorly investigated in animals of interest to veterinary forensic pathology. The aim of this study was to investigate the potential use of muscle proteins (desmin and dystrophin) as biomarkers for estimating the PMI in dogs. For this study, 10 dead adult dogs were evaluated for 4 days in a temperature-controlled room at 19 ± 1 °C. For each animal, at 3, 24, 48, 72, and 96 h after death, a 1 × 1 × 1 cm cube of muscle tissue was removed from the vastus lateralis and triceps brachii. Protein expression levels were analyzed by immunohistochemical examination and immunoblot analysis. The obtained results showed rapid dystrophin degradation, with complete disappearance at 72 h after death. In contrast, desmin-positive fibers and desmin protein bands detected by immunoblot were observed on all 4 days of observation. Our findings suggest the potential use of muscle proteins as biomarkers for estimating the PMI in dogs.