title: [Relation between PMI and FTIR spectral changes in asphyxiated rat's liver and spleen].
abstract: OBJECTIVE
  Fourier transform infrared (FTIR) spectroscopy was applied to observe the postmortem degradation process in mechanical asphyxiated rat's liver and spleen for providing a new method of estimating PMI.
  
  
  METHODS
  Rats were sacrificed by mechanical asphyxia and cadavers were kept at (20 +/- 2) degrees C in a control chamber. The liver and spleen were sub-sampled from the same rat at intervals of 0-15 days postmortem and the data were measured by FTIR spectrometer. The different absorbance (A) ratios of peaks were calculated and the curve estimation analysis between absorbance ratios (x) and PMI (y) were performed to establish mathematical models by the statistical software.
  
  
  RESULTS
  The band absorbance ratios showed increase, decrease and stable with PMI. The cubic model functions showed the strongest correlation coefficient. Compared with the spleen, the liver showed a higher correlation coefficient. The A1541/A1396 of liver showed the highest correlation coefficient (r=0.966). After 6-7 days postmortem, band absorbance ratios showed a steady period.
  
  
  CONCLUSIONS
  FTIR spectroscopy can be a new and efficient method to estimate PMI within 7 days.
authors.affiliation: Department of Forensic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China. 11211010057@fudan.edu.cn
authors.forename: Shi-ying
authors.initials: SY
authors.lastname: Li
authors.forename: Yu
authors.initials: Y
authors.lastname: Shao
authors.forename: Zheng-dong
authors.initials: ZD
authors.lastname: Li
authors.forename: Dong-hua
authors.initials: DH
authors.lastname: Zou
authors.forename: Zhi-qiang
authors.initials: ZQ
authors.lastname: Qin
authors.forename: Yi-jiu
authors.initials: YJ
authors.lastname: Chen
authors.forename: Ping
authors.initials: P
authors.lastname: Huang
mesh_terms: D000818:Animals; D001237:Asphyxia / Q000378:metabolism*; D001344:Autopsy; D002102:Cadaver; D049429:Forensic Pathology / Q000379:methods; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008962:Models, Theoretical; D011180:Postmortem Changes; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D017550:Spectroscopy, Fourier Transform Infrared; D013154:Spleen / Q000378:metabolism* / Q000473:pathology; D013997:Time Factors