The Application Of The Human Skeleton In Late Postmortem Interval

Objective: The aim of this research was to explore the relationship among the morphology and structure changes of femurs in corpses of decompose tony skeleton with different time after death, content of plumbum、cadmium、hydrargyrum and DNA in femur and late postmortem interval. Methods: 1. Fifteen corpses of decompose tony skeleton of which time after death was exactly known were buried in the same natural environment. Femurs were collected from them once a year in three years. 2. Femurs were cut into bone slices. The morphology and structure changes of femurs with different time after death were observed with microscope. 3. The content of plumbum and cadmium were measured by graphite furnace atomic absorption spectrometry. The content of hydrargyrum was detected by atomic fluorescence spectrometry. The data was analyzed by SPSS 19.0 software. Curve fitting was made between the content of plumbum、cadmium、hydrargyrum and late postmortem interval in order to analyze the application of the content of these three kind of element in late postmortem interval. 4. DNA was extracted from cleaning, decalcifying femurs, amplified by PCR and genotyped by capillary electrophoresis. DNA was quantified by the real-time fluorescence quantitative PCR. Curve fitting was made between the content of DNA and late postmortem interval by the SPSS 19.0 software. Results: 1. The changes of the organizational structure of femurs under the microscope had a certain regularity. According to made linear and curve fitting among the amount of osteon and central canal and late postmortem interval, we got the regression equations between the osteon and late postmortem interval and the regression equations between the central canal and late postmortem interval, respectively. 2. The content of plumbum、cadmium and hydrargyrum in femurs with different postmortem interval were analyzed by Friedman test and regression analysis. The results showed that there was certain interdependency among cadmium, hydrargyrum and late postmortem interval but not between plumbum and late postmortem interval. 3. Full profiles with twenty-four STR loci were successfully obtained from femurs of 15 corpses. 4. According to real-time fluorescence quantitative PCR analysis, curve fitting was made between among Ct, Qty and late postmortem interval. But P values were all greater than 0.05, and there was no statistically significance. Conclusion: 1.The morphology and structure of femurs changed with the late postmortem interval extension. The changes of amount of osteon and central canal were helpful to estimate the late postmortem interval. 2. The changes of the content of cadmium in the femur could be a new method to estimate the late postmortem interval. However, the relationship among the content of hydrargyrum and late postmortem interval needed a further investigation, and plumbum was no use about this. 3. These methods in our research were simple and rapid, and could be applied to DNA extraction.