Assessing post-mortem interval in cats (Felis catus) through RNA degradation analysis in liver tissue

Area of Science:

• Forensic veterinary pathology
• Biomolecular analysis
• Post-mortem interval estimation

Background:

• Accurate post-mortem interval (PMI) estimation is crucial in forensic veterinary pathology.
• Environmental temperature significantly impacts decomposition rates and PMI accuracy.
• Accumulated Degree Days (ADDs) are used to quantify thermal exposure.
• RNA-based techniques show potential for PMI estimation due to RNA's instability post-mortem.

Purpose of the Study:

• To evaluate the utility of RNA integrity parameters (RIN and DV200) and specific mRNA levels for estimating PMI in deceased cats.
• To correlate RNA degradation patterns with environmental conditions (in field vs. refrigerated) and Accumulated Degree Days (ADDs).

Main Methods:

• Post-mortem liver tissue sampling from 54 deceased cats under controlled conditions (in field, refrigerated, and controls).
• Calculation of Accumulated Degree Days (ADDs) based on environmental temperatures.
• Analysis of RNA integrity using microfluidic electrophoresis to obtain RIN and DV200 values.
• Quantification of target reference gene mRNA degradation using qPCR and ddPCR.

Main Results:

• A statistically significant reduction in RIN, DV200, and RPL17-mRNA was observed in cats exposed to "in field" conditions within the 51-200 ADDs range.
• Similar degradation patterns for RIN, DV200, and GAPDH-mRNA were noted in "refrigerated" cats at 14 and 28 days post-mortem compared to controls.
• RIN and DV200 demonstrated potential as reliable biomarkers for distinguishing recent deaths from those exceeding 50 ADDs.

Conclusions:

• RNA Integrity Number (RIN) and DV200 are promising biomarkers for post-mortem interval estimation in cats.
• These RNA-based parameters are valuable for differentiating between recent deaths and those occurring beyond 50 ADDs, especially under varying environmental conditions.
• Further research can refine these molecular techniques for more precise PMI determination in forensic veterinary cases.