Determination Of Pmi By Splenic Lymphocytes Changes With Computerized Image Analysis Technique

We analyzed grayscale and geometric changes of splenic lymphocytes after DNA degradation by computerized image analysis technique (CIAT), and evaluated the correlation between DNA degradation of the splenic lymphocytes and the corresponding postmortem interval (PMI). The spleen tissues from 30 cadavers with known PMI were collected, subjected to cell smearing every hour within the first 5-36 h after death, stained by Feulgen's staining, three grayscale parameters reflecting DNA content in splenic lymphocytes, including integral optical density (IOD), average optical density (AOD), average gray scale (AG), and five geometric parameters reflecting DNA discrete distribution, including area (A), equivalent diameter (ED), average diameter (AD), perimeter (P), index of density (ID). Our results showed that IOD and AOD decreased, AG and ID increased within the first 5-36 h. A stepwise linear regression analysis showed that AG, AOD, IOD and ID were fitted respectively. A statistical correlation between the PMI and AG, AOD, IOD, ID was identified, and the corresponding regression equation was obtained. Whereas, A, P, ED and AD did not show statistical correlation with the corresponding PMI. Our study suggests that CIAT is a useful to estimate early PMI, AG, AOD, IOD and ID are valid quantitative indicators to infer the early PMI in human.