[Correlation between five RNA markers of rat's skin and PMI at different temperatures].

Objective To explore the correlation between postmortem interval(PMI) and five RNA markers of rat's skin—β-actin, glyceraldehyde-3-phosphate dehydrogenase(GAPDH), 18 S ribosomal RNA(18S rRNA), 5S ribosomal RNA(5S rRNA), and microRNA-203(miR-203), at different temperatures. Methods Eighteen SD rats were randomly divided into three environmental temperature groups:4 ℃, 15 ℃ and 35 ℃, respectively. Skin samples were taken at 11 time points from 0 h to 120 h postmortem. The total RNA was extracted from the skin samples and the five RNA levels were detected by real-time fluorescent quantitative PCR. Proper internal reference was selected by geNorm software. Regression analysis of the RNA markers was conducted by GraphPad software. Results 5S rRNA and miR-203 were most suitable internal references. A good linear relationship between PMI and RNA levels(β-actin and GAPDH) was observed in two groups(4 ℃ and 15 ℃), whereas the S type curve relationship between the expression levels of the two markers(β-actin and GAPDH) and PMI was observed in the 35 ℃ group. The partial linear relationship between 18 S rRNA and PMI was observed in the groups(15 ℃ and 35 ℃). Conclusion Skin could be a suitable material for extracting RNA. The RNA expression levels of β-actin and GAPDH correlate well with PMI, and these RNA markers of skin tissue could be additional indice for the estimation of PMI.