title: Exploration of the R code-based mathematical model for PMI estimation using profiling of RNA degradation in rat brain tissue at different temperatures.
abstract: Precise estimation of postmortem interval (PMI) is crucial in some criminal cases. This study aims to find some optimal markers for PMI estimation and build a mathematical model that could be used in various temperature conditions. Different mRNA and microRNA markers in rat brain samples were detected using real-time fluorescent quantitative PCR at 12 time points within 144 h postmortem and at temperatures of 4, 15, 25, and 35 °C. Samples from 36 other rats were used to verify the animal mathematical model. Brain-specific mir-9 and mir-125b are effective endogenous control markers that are not affected by PMI up to 144 h postmortem under these temperatures, whereas the commonly used U6 is not a suitable endogenous control in this study. Among all the candidate markers, ΔCt (β-actin) has the best correlation coefficient with PMI and was used to build a new model using R software which can simultaneously manage both PMI and temperature parameters. This animal mathematical model is verified using samples from 36 other rats and shows increased accuracy for higher temperatures and longer PMI. In this study, β-actin was found to be an optimal marker to estimate PMI and some other markers were found to be suitable to act as endogenous controls. Additionally, we have used R code software to build a model of PMI estimation that could be used in various temperature conditions.
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Jianlong
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Hui
authors.initials: H
authors.lastname: Pan
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Yehui
authors.initials: Y
authors.lastname: Lv
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Aimin
authors.initials: A
authors.lastname: Xue
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China.
authors.forename: Jieqing
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Forensic Lab, Criminal Science and Technology Institute, Shanghai Public Security Bureau, 803 North Zhongshan Road, Shanghai, 200082, People's Republic of China. makaijun@sina.cn.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Ma
authors.affiliation: Department of Forensic Medicine, Shanghai Medical School of Fudan University, 131 Dongan Road, Shanghai, 200032, People's Republic of China. chenlong@shmu.edu.cn.
authors.forename: Long
authors.initials: L
authors.lastname: Chen
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D005819:Genetic Markers; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism; D023421:Models, Animal; D008962:Models, Theoretical; D011180:Postmortem Changes; D020871:RNA Stability; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D012984:Software; D013048:Specimen Handling; D013696:Temperature
chemical_list: D000199:Actins; D005819:Genetic Markers; C581261:MIRN125 microRNA, rat; C582333:MIRN9 microRNA, rat; D035683:MicroRNAs
keywords: Postmortem interval (PMI); R code; RNA; Reverse transcription quantitative real-time PCR