Calculating post-mortem interval by using the morphological changes in leucocytes.

Abstract

The changes in the internal environment of the body after death due to lack of oxygen result in certain morphological changes in the blood cells. This study tests the hypothesis that after we take out blood from live individuals and store it in-vitro there will also be an anoxic environment which will result in morphological changes like what happens in-vivo after death. The idea was to simulate the anoxic in-vivo condition in-vitro, by storing the blood sample taken from live persons in a vial and to look for sequential changes with respect to time and to develop a scale to see how this scale of morphological changes correlates with the time since death in post-mortem samples collected. Blood samples preserved in EDTA was taken from 186 live volunteers and 60 cadavers whose exact time of death was known. Blood smear was made and stained with Leishman stain and observed under an oil immersion microscope. Cells were classified into four stages based upon the nuclear changes - normal, pyknosis (shrunken nucleus), vacuolated and fragmented nucleus and complete lysis. The sequence of change remained same in both in-vitro stored samples and cadaver in-vivo samples. But the changes in the cadaver samples were appearing rapidly as compared to the in-vitro stored samples. It is hard to completely refute the hypothesis that in-vitro and cadaver conditions would be similar, and changes exhibited would also be similar based on this single study. Further studies with much larger sample size need to be conducted to completely refute or prove the above hypothesis. Also, other co-existing factors which can affect morphology of the cells should be considered.