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Published on: January 17, 2019
Postmortem interval determination using 18S-rRNA and microRNA
Wen-Can Li1, Kai-Jun Ma2, Ye-Hui Lv3
1Forensic Department, Shanghai Medical College, Fudan University, Shanghai 200032, China; Shanghai City Public Security Bureau, Shanghai 200032, China.
Abstract:
The importance of determining postmortem interval (PMI) is crucial to criminal, civil and forensic cases. The precise estimation of PMI is a critical step in many death investigations. A technique exploiting the level of RNA, 18S rRNA and microRNA to estimate PMI was investigated. 18S-rRNA is a main ribosomal RNA presented as part of the ribosomal protein complex, while microRNA is a class of small non-coding single-stranded RNA, only 21-25 nucleotides, which has a strong conservation between different species. In this study, heart tissues were removed from adult rats at various postmortem intervals. An efficient extraction and detection protocol to analyze the level of 18S-rRNA and microRNA in postmortem tissue was carried out. The process consists of total RNA extraction, transcription and visualization by quantitative real time PCR. The result indicates a characteristic parabola relationship between postmortem period and Ct values for 18S-rRNA in dead rat hearts. The result indicates that the degradation pattern of tissue 18S-rRNA and microRNA is useful in the determination of the postmortem interval within seven days.
Insights
Determining the time of death is vital in forensic science. This study shows that analyzing ribosomal RNA (rRNA) and microRNA degradation in heart tissue can accurately estimate the postmortem interval (PMI) within seven days.
Area of Science:
- Forensic Science
- Molecular Biology
- Biochemistry
Background:
- Accurate postmortem interval (PMI) estimation is critical for legal and forensic investigations.
- Current methods for PMI determination have limitations.
- RNA degradation patterns offer a potential biomarker for PMI.
Purpose of the Study:
- To investigate the utility of 18S ribosomal RNA (rRNA) and microRNA levels for estimating PMI.
- To develop and validate an RNA-based protocol for PMI determination.
Main Methods:
- Heart tissues from rats were collected at various postmortem intervals.
- A protocol involving total RNA extraction, transcription, and quantitative real-time PCR was employed.
- Levels of 18S rRNA and microRNA were analyzed.
Main Results:
- A distinct parabolic relationship was observed between the postmortem period and Ct values for 18S rRNA in rat heart tissue.
- Degradation patterns of 18S rRNA and microRNA showed utility in PMI estimation.
Conclusions:
- The degradation patterns of 18S rRNA and microRNA in postmortem heart tissue are reliable indicators for PMI determination.
- This RNA-based method can estimate PMI within the first seven days postmortem.
