组织中三甲胺-氮浓度变化与晚期PMI关系初探

目的探索死后尸体组织中三甲胺-氮(TMA-N)浓度变化规律及其与晚期死亡时间的关系。方法健康SD大鼠66只,颈椎脱臼法处死,随机分成11组,分别于死后即刻、1、2、3、4、5、6、7、8、9、10d取大鼠肌肉、肝脏和肾脏组织,用分光光度法检测TMA-N浓度,所得数据用方差分析比较组间差异性,并进行回归方程拟合。结果3种组织中TMA-N含量随死后时间延长而增加,肌肉于死后7d、肝脏和肾脏于死后8d达到高峰,之后有所下降,并均于死后10d再次升高,肝、肾组织之间TMA-N含量比较无统计学差异性。死后2~7d内,PM I与肌肉TMA-N浓度变化拟合度最高(R2=0.969);死后3~8d内,与肝肾中TMA-N浓度变化拟合度最高(R2=0.953)。结论死后组织中TMA-N含量变化与PM I有相关性,可望为晚期PM I推断提供参考,但肌肉与肝肾TMA-N含量变化规律存在一定差异,需选择最适时段以提高PM I推断的准确性。

A pilot study to investigate the relationship between concentration of trimethylamine-nitrogen in corpse tissue and late postmortem interval estimation

】Objective To study the relationship between changes of the concentration of trimethylamine-nitrogen(TMA-N) in tissues of cadaver and late postmortem interval(PMI).Methods Sixty-six healthy SD rats were sacrificed by cervical vertebrae dislocation and their muscles,livers and kidneys were sampled at intervals of 0,1,2,3,4,5,6,7,8,9 and 10d since death.The concentration of TMA-N was detected using spectrophotometric method.Analysis of variance and regression analysis were carried out on the data.Results The concentration of TMA-N in three tissues increased while PMI was prolonged.The TMA-N peak in muscle tissue appeared on the 7th day since death and that in liver and kidney tissues appeared on the 8th day since death.After that,the TMA-N concentration began to decline and on the 10th day,it increased once again.The difference in concentration of TMA-N in liver and kidney was not statistically noticeable.There was strongest correlation between PMI and TMA-N concentration in muscle(R2=0.969) as from 2d to 7d since death.From 3d to 8d since death,there was strongest correlation between PMI and TMA-N concentration in liver-kidney(R2=0.953).Conclusion There was correlation between TMA-N concentration in tissues and PMI.This may further help to narrow the estimation of PMI.There was statistical difference between the concentration of TMA-N in muscle and that from internal organs after death.Choosing the optimal range of time was warranted for more accurate estimation of PMI.