title: [Estimation of postmortem interval using microRNA and 18S rRNA degradation in rat cardiac muscle].
abstract: OBJECTIVE
  To explore the relationship between the time-dependent level changes of microRNA and 18S rRNA and the different postmortem interval (PMI) in rat cardiac muscle.
  
  
  METHODS
  SD rats were sacrificed by cervical dislocation and placed at ambient temperature 25 degrees C with a humidity of 50%. Total RNA was extracted from the rat cardiac muscle at different time points after death. The levels of miR-1-2 and 18S rRNA were examined using real-time PCR in rat cardiac muscle. The results were expressed by cycle threshold (Ct) value to explore relationship between PMI and Ct value, and the regression functions were established to estimate PMI.
  
  
  RESULTS
  The miR-1-2 level in rat myocardial tissue showed no significant changes within 120 h after death, and then began to decline. The 18S rRNA level increased gradually within 96 h after death, and then declined slowly. The nonlinear relationships were established between Ct value (18S rRNA), deltaCt value (difference between 18S rRNA and miR-1-2) and PMI. The R2 of conics fitting were 0.9487 and 0.8072, respectively.
  
  
  CONCLUSIONS
  Ct value of 18S rRNA and deltaCt value present a good correlation with PMI, and can be markers for estimating early PMI.
authors.affiliation: Department of Forensic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China. 082101058@fudan.edu.cn
authors.forename: Wen-can
authors.initials: WC
authors.lastname: Li
authors.forename: Kai-jun
authors.initials: KJ
authors.lastname: Ma
authors.forename: Ping
authors.initials: P
authors.lastname: Zhang
authors.forename: Hui-jun
authors.initials: HJ
authors.lastname: Wang
authors.forename: Yi-wen
authors.initials: YW
authors.lastname: Shen
authors.forename: Yue-qin
authors.initials: YQ
authors.lastname: Zhou
authors.forename: Zi-qin
authors.initials: ZQ
authors.lastname: Zhao
authors.forename: Duan
authors.initials: D
authors.lastname: Ma
authors.forename: Long
authors.initials: L
authors.lastname: Chen
mesh_terms: D000818:Animals; D049429:Forensic Pathology; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D011180:Postmortem Changes; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000235:genetics / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013997:Time Factors
chemical_list: D035683:MicroRNAs; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S