A Study On The Relationship Between Postmortem Interval And The Changes Of DNA Content In Schwann Cells Of Rat's Sciatic Nerve And The Expression Of S-100β In The Rat's Brain

Objective To study changes of DNA content in Schwann cells of rat's sciatic nerve and the expression of S-100βin the rat's brain with the postmortem interval, trying to provide objective support for estimating of PMI. Methods (1) Using Feulgen staining methods of DNA and the computeriz-ed image analysis to measure the DNA content in Schwann cells of rat's sciatic nerve during 9d after death. (2)The expression of S-100βin the rat's brain was performed by immunohistochemical technique at every 2h during 12h after death and results were assessed by image analysis system. Results (1) The color and the areas of the nuclei stained with the Feulgen staining method became fainter and smaller gradually within 12h.There was a certainty relationship between the degradation rate of the nuclear DNA and the PMI (in 9d) of rat. (2)The expression of S-100βin the rat's brain has an apparent relationship to early PMI (in 12h) of rat, and gets regress equation. Conclusion (1) It is possible to estimate the PMI by determining the quantity of DNA in sciatic nerve should be an objective and exact way to estimate the PMI. (2)Determining the quantity of S-100βin brain by immunohistochemical technique should be an objective and exact way to estimate the PMI.