Zhu Yi, Dong Ying-Chun, Liang Wei-Bo, Zhang Lin
West China School of Preclinical and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Fa Yi Xue Za Zhi. 2011 Jun;27(3):161-3, 177.
To investigate the degradation changes of beta-actin mRNA and 18S rRNA in different time points and temperature after death, and to explore the relationship between the changes and postmortem interval (PMI) in the brain of mice.
Twenty-four health adult C57BL/6 mice were randomly divided into two groups (12 each group). They were sacrificed by cervical dislocation and placed in chamber with two different temperature (4 degrees C and 37 degrees C, humidity was 80%). The mice brains were sampled at 6 different time points(immediately, 0.5h, 2h, 6h, 24h, 48h), and total brain RNA were extracted. Ct value of each sample was obtained using RT-PCR and real-time PCR technology, and beta-actin mRNA and 18S rRNA content ratio was calculated. The correlation between the content ratio and PMI was expressed using statistical regression analysis.
At 37 degrees C, RNA degradation rate was faster than 4 degrees C, which showed that there was correlation between temperature and RNA degradation. Comparing with the stability of beta-actin mRNA, 18S rRNA was more stable.
The study on degradation of beta-actin mRNA and 18S rRNA in mice brain using real time PCR technology could provide a new theoretical basis for estimation of PMI and would be supplementary to the traditional methods.
研究小鼠死后不同时间点及温度条件下β-肌动蛋白mRNA和18S rRNA的降解变化，探讨其变化与死后间隔时间（PMI）的关系。
将24只健康成年C57BL/6小鼠随机分为两组（每组12只）。通过颈椎脱臼法处死小鼠，并置于两种不同温度（4℃和37℃，湿度80%）的环境中。在6个不同时间点（即刻、0.5小时、2小时、6小时、24小时、48小时）采集小鼠脑组织，提取总RNA。采用RT-PCR和实时荧光定量PCR技术获取每个样本的Ct值，计算β-肌动蛋白mRNA与18S rRNA的含量比值。运用统计回归分析表达含量比值与PMI之间的相关性。
在37℃时，RNA降解速度比4℃时快，表明温度与RNA降解存在相关性。与β-肌动蛋白mRNA的稳定性相比，18S rRNA更稳定。
应用实时荧光定量PCR技术研究小鼠脑组织中β-肌动蛋白mRNA和18S rRNA的降解，可为PMI的推断提供新的理论依据，并对传统方法起到补充作用。
