死亡人体胸肌组织中rRNA亚基的稳定性评价

目的观察尸体胸大肌组织中rRNA各亚基表达水平的死后稳定性,探讨其在死亡时间推断中应用的价值。方法选取6例（3例成人、3例婴幼儿）外界温、湿度环境基本一致、死亡时间基本一致（24h以内）的个体,提取左侧胸大肌组织,在PBS缓冲液中低温冻存,分别在尸检即刻、2、3、4、5、6、7、8、9、10d提取微量组织保存于RNA固定液中,通过实时荧光定量RT-PCR技术检测rRNA 5srRNA、5.8srRNA、18srRNA、28srRNA亚基的表达水平。并分析年龄、死因对rRNA亚基表达水平的影响。结果死后各时间点rRNA各亚基的表达随死后经过时间延长无显著性降解,Ct值变化与死后经过时间无相关性（P值均大于0.05）,其中5s rRNA在18.503±2.655~20.937±2.340之间,5.8s rRNA在17.687±3.011~20.617±2.204之间,18s rRNA在16.457±3.920~22.330±2.571之间,28s rRNA在15.077±6.051~22.207±2.685之间。结论人体胸肌组织中rRNA各亚基稳定性好,其各亚基的表达量与死因、年龄无关,适于作为晚期死亡的推断的内参基因。

Stability of rRNA subunits in human breast muscle tissue after death

Objective To investigate the stability of rRNA subunits expression levels in human breast muscle tissue after death,the application value in estimation of time since death was analyzed.Methods Left breast muscle in three adults and three infants were collected respectively in one day until the ten day,sample tissues were preserved in RNA fixative solutions,Real-time quantitative RT-PCR were used to detect rRNA subunits（ 5srRNA,5.8srRNA,18srRNA,28srRNA） expression levels.The relationship between age,cause of death and postmortem interval were also analyzed.Results The expression level of rRNA subunits showed no significant degradation,changes of Ct values showed no correlation with postmortem interval after death（ P 0.05）,and showed no correlation with the cause of death,age.Ct values of 5s rRNA was in the range of 18.503 ± 2.655 ~ 20.937 ± 2.340,Ct values of 5.8srRNA was in the range of 17.687 ± 3.011 ~ 20.617 ± 2.204,Ct values of 18srRNA was in the range of 16.457 ± 3.920 ~ 22.330 ± 2.571,Ct values of 28s rRNA was in the range of 15.077 ± 6.051 ~ 22.207 ± 2.68.Conclusion The expression of rRNA subunits showed good stability,suitable as inferred reference gene in corrupt corpse.Age,cause of death has no relation with the expression level of rRNA subunits.