The Changes of Fourier Transform Infrared Spectrum in Rat Brain*

Abstract

Estimation of the time since death (postmortem interval [PMI]) is one of the most difficult problems in forensic investigations, and many methods currently are utilized to estimate the PMI. The goal of this study was to investigate the changes of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra of rat brain from postmortem time 0-144 h. The intensity ratios of major absorbance bands were examined (I(1066)/I(1392), I(1168)/I(1392), I(1234)/I(1454), I(1301)/I(1392), I(1647)/I(2956), I(2921)/I(2850), and I(1647)/I(1539)). The spectra of rat brain displayed prominent changes with increasing PMI. The band at 2871 and 1737 per cm became weak with the time increasing and even disappeared at postmortem 96 and 72 h, respectively. A close linear correlation was shown between the relative absorption intensity and the PMI, and the I(1234) /I(1454) offered a stronger correlation (r = 0.973). Our results indicate that ATR-FTIR spectroscopy may be a useful technique for estimating the PMI.

Investigation of gene expressions in differentiated cell derived bone marrow stem cells during bone morphogenetic protein-4 treatments with Fourier transform infrared spectroscopy

“…The ratio between the peak areas of CH 2 symmetric and CH 2 asymmetric stretching was increased by differentiation progression (Figure 5b). In recent years, CH2 symmetric/CH2 asymmetric band was attributed to changes in the cell membrane (39). Our study might reflect a clear change in the membrane of cells in the differentiation procedure.…”

“…At least three areas of variation were found by comparing the ratios of bands :There are two peaks at about 2850 and 2920 cm -1 , which can be related to the CH 2 symmetric andCH 2 asymmetric stretching vibration bands, respectively (39). The ratio between the peak areas of CH 2 symmetric and CH 2 asymmetric stretching was increased by differentiation progression (Figure 5b).…”

Animal experimentation in forensic sciences: How far have we come?

“…"Euthanasia" methods included the "humane" injection of sodium pentobarbital, but also exsanguination and blunt trauma [29,30,31]. In some cases, the type of trauma examined or the actual experiment ended up being the cause of death [32,33,34].…”

Characterization of postmortem biochemical changes in rabbit plasma using ATR-FTIR combined with chemometrics: A preliminary study

“…Our work is focused on the characterization of postmortem changes in biological tissues with the ATR-FTIR technique in order to determine the time after death. In our previous studies, it has been demonstrated that various absorption intensities or area ratios in an infrared spectrum are strongly correlated with PMI in human and animal tissues including brain, kidney cortex, cardiac muscle and lung [19][20][21][22][23] . However, these studies did not make full use of ATR-FTIR for PMI delimitation because only a few parameters were taken into consideration.…”