5 miRNA expression analyze in post-mortem interval (PMI) within 48 h

MicroRNAs (miRNAs) are small, noncoding RNA molecules with an important role in regulating gene expression at the posttranscriptional level. They present interesting characteristics in forensic science, such as bodyfluid-special expression, tissue-special expression and stability at post-mortem. We purposed a preliminary study on mice, to analyzing the 5 miRNAs expression pattern in PMI within 48 h. 33 adult C57 male mice were randomly grouped into 10 PMI time points within 48 h under the room temperature and 0 h (just after death), with 3 mice in each group. The cardiac muscle, liver, brain and skeletal muscle were collected from each mouse and stored at -80 degrees C. Total RNA was extracted using an RNAiso Reagent following RT and SYBR assay of reatime PCR. After the results were normalized against U6B, we found that in the first 24 h of PMI, all 5 target miRNA from liver tissue did not show any correlation, but between 24 and 48 h, 3 miRNAs decreased obviously. The result shows that miRNAs present good stability in the first 24 h of PMI, and some of them begin to decrease after 24 h. Therefore, before we study on the miRNA of PMI, the miRNA degradation patterns should be analyzed at first. (C) 2013 Elsevier Ireland Ltd. All rights reserved.