Abstract: Objective To study changes of DNA content in the kidney cellule of rats and relationship with the postmortem interval.Methods This experiment chose seven parameter of cell nuclear,including the area and integral optical density,determined the changes of DNA content in the kidney cellule of 15 rats at different intervals between 0 and 48h postmortem with auto－ TV－ image system.Results The degradation rate of DNA in nuclear has a certainty relationship to early PMI(in 48h) of rat,and get binomial regress equation. Conclusion Determining the quantity of DNA in nuclear should be an objective and exact way to estimate the PMI. [

Key words: PMI, image analysis, rat, kidney, DNA, degradation