[Study on the correlation between PMI and OD changes in rat's plasma].
We chose the UV-Vis spectrophotometry as a new way to investigate the postmortem interval (PMI). One hundred fifty Sprague-Dawley female rats (weight 260 g +/- 10 g, from Xi'an Jiaotong University Animal Center) were chosen and sacrificed by cervical dislocation. The bodies were kept in a controlled environmental chamber set at (20 +/- 2) degrees C. The plasma was harvested in course of 0 to 24 hours after death. The optical density (OD) at different wavelengths was measured with an UV-Vis spectrophotometer (type-UV250). It was shown that the OD changes of plasma at 577, 416 and 275 nm in 24 hours were dramatically related to PMI, and the R-indexes were 0.969, 0.97 and 0.898. The regression formulae of these indexes were worked out taking OD as independent variable, and PMI as variable. The quadratic equations were: PMI = 231.2270D(plasma at wavelength of 577 nm) - 501.160D(plasma at wavelength of 577 nm)2 - 3.0809(R2 = 0.945), PMI = 31.7426OD(plasma at wavelength of 416 nm) - 9.1847OD(plasma at wavelength of 416 nm)2 - 31837(R2 = 0.94), and PMI = 95.2388OD(plasma at wavelength of 275 nm) - 39.343OD(plama at wavelength of 275 nm)2 - 32.408(R2 = 0.795). It was concluded that the OD changes of rat's plasma are good and potential markers for the estimation of PMI and should be very useful in forensic practice.
Li
Wei
W
Department of Forensic Medicine, Xi'an Jiaotong University, Xi'an 710061, China.
Ke
Yong
Y
He
Guang-she
GS
Xu
Yong-cheng
YC
Wang
Zhen-yuan
ZY
D000818:Animals; D005260:Female; D010949:Plasma / Q000737:chemistry*; D011180:Postmortem Changes; D051381:Rats; D017207:Rats, Sprague-Dawley; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors