中文摘要：

目的应用傅里叶变换红外（Fourier transform ininfrared，FTIR）光谱技术观察窒息死大鼠肝、脾组织的光谱变化规律，寻找推断死亡时间的新方法。方法将大鼠机械性窒息处死后．尸体保存于（20±2）℃的环境下，提取死后15d内各时间点肝、脾组织样本，进行红外光谱测量，运用统计软件推导大鼠死后肝、脾组织不同区域的吸收峰吸光度（A）比值（x）对死亡时间（y）拟合的数学模型。结果吸光度比值随大鼠死亡时间的延长呈上升、下降及保持稳定3个趋势。最佳拟合曲线为三次方曲线，肝较脾的拟合相关系数高．其中肝A1541/A1396的相关系数最高（r=0．966）。大多数吸光度比值从死后6～7d开始呈平台期。结论FTIR光谱技术作为推断死亡时间的新方法，在推断7d以内的死亡时间具有一定的应用价值。

英文摘要：

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 esti- mating PMI. Methods Rats were sacrificed by mechanical asphyxia and cadavers were kept at （20±2） ℃ 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 clays postmortem, band absorbance ratios showed a steady period. Conclusion FTIR spectroscopy can be a new and efficient method to estimate PMI within 7 days.