Metabolic profiling of femoral muscle from rats at different periods of time after death

Abstract

Clarification of postmortem metabolite changes can help characterize the process of biological degradation and facilitate investigations of forensic casework, especially in the estimation of postmortem interval (PMI). Metabolomics can provide information on the molecular profiles of tissues, which can aid in investigating postmortem metabolite changes. In this study, liquid chromatography-mass spectrometric (LC-MS) analysis was performed to identify the metabolic profiles of rat femoral muscle at ten periods of time after death within 168 h. The results obtained by reversed-phase liquid chromatography (RPLC)- and hydrophilic interaction liquid chromatography (HILIC)- electrospray ionization (ESI±) have revealed more than 16,000 features from all four datasets. Furthermore, 915 of these features were identified using an in-house database. Principal component analysis (PCA) demonstrated the time-specific features of molecular profiling at each period of time after death. Moreover, results from partial least squares projection to latent structures-discriminant analysis (PLS-DA) disclosed a strong association of metabolic alterations of at least 59 metabolites with the time since death, especially within 48 h after death, which expounds these metabolites as potential indicators in PMI estimation. Altogether, our results illustrate the potentiality of metabolic profiling in the evaluation of PMI and provide candidate metabolite markers with strong correlation with time since death for forensic purpose.

Microbiota and metabolome responses in the cecum and serum of broiler chickens fed with plant essential oils or virginiamycin

“…Dopamine is a major transmitter in the extrapyramidal system of the brain and is important in regulating movement. A family of receptors (dopamine receptors) mediates action, which plays a major role in the reward-motivated behaviour 35 . The enrichment of the relative abundance of Phyla Bacteroidetes and genera Alistipes, unclassified Rikenellaceae might be related with biosynthesis of fatty acid and lipid metabolism.…”

Recent Developments along the Analytical Process for Metabolomics Workflows

“…In this regard, metabolomics analysis can help not only in clarifying possible post-mortem (PM) changes within the tissue to improve the reliability of the interpretation of the results but also in forensics, cancer, and transplantation research. 28 To unveil metabolic markers correlated with the PMI, Du et al 29 performed an untargeted metabolomics analysis of femoral muscle from Sprague−Dawley rats based on both HILIC and RP-LC−MS/MS. The authors investigated the metabolic shifts from PMIs of 10 to 168 h, and they concluded that the greatest changes occurred after 48 h PM, highlighting 19 metabolites that could serve as possible indicators to increase accuracy when determining the time of death.…”

Untargeted metabolomics approaches to improve casework in clinical and forensic toxicology—“Where are we standing and where are we heading?”

“…Similarly, a comprehensive untargeted LC-MS-based metabolomics approach by Du et al investigated the metabolic profiles of rat femoral muscle over a 168 h PMI and using PLS-DA found changes of 59 features with strong associations to the PMI, predominantly within 48 h after death. Of these, 19 endogenous metabolites were positively identified using an in-house database and included, for example, also niacinamide (Du et al, 2018). However, data on the validation of proposed biomarkers in humans is sparse, due to the ethical constraints for controlled human studies.…”