死亡方式对大鼠DNA降解影响的图像分析研究

探讨不同的死亡方式对组织细胞核 DNA 降解的速率是否存在影响。选取20只大鼠随机分为4组,分别采用失血性休克、断颈、溺死及扼死等4种方式处死,每2 h 取材一次(脑、脾、肝组织),Carnoy 液固定,VANS 改良法染色,选取7个指标进行图像分析,数据经一元回归及多元回归统计处理,对不同死亡方式组的一元回归方程进行多组间分析。结果显示,7个指标与死亡时间明显相关,但在不同死亡方式组间各指标相关性存在差异,一元回归方程比较显示,溺死组与其他组肝组织 ID、AOD、LDC 3个指标存在差异,显示其 DNA 降解较慢,脾脏在溺死组 A、MD、ID、AOD、LDC、AG 等6个指标以及失血性休克组 MD、ID、AOD、AG 等4个指标与其他组间存在明显差异,而脑组织在不同组间则差异较小。多元回归分析进一步印证了上述差异。在失血性休克、溺死、断颈及扼死致死的尸体间其组织细胞 DNA 降解速率存在差异,其原因可能与淤血程度及尸体所处环境有关。在本实验条件下,脑是受影响最小的器官,而脾是较易受影响的器官。

A study of the influence on the DNA degradation rate exerted by the different manner of death

To study whether the different manner of death influences on the DNA degradation speed. Twenty mice were divided into four groups which included animals killed by breaking neck,hemorrhagic shock,manual strangulation,and drowning respectively.Speen,liver and brain were removed every two hours and then fixed in the cold Carnoy solution for thirty minutes,stained with the modified Vans method followed by image analysis with 7 indexes.A univariate regession analysis and a multivariate regression analysis were conducted.The data of different groups were compared.The results showed that there was an obvious relationship between the seven indexes and the postmortem intervals(PMI),but the relationsip between various indexes and organs were different.The results of the univariate regression analysis indicat- ed that the indexes of ID,AOD,LDC of liver taken from the drowning group were different from those of other three groups.The speed of DNA degradation was slow.The indexes including A,MD,ID,AOD, LDC,AG of spleen in the drowning group and the indexes including MD,ID,AOD and AG of spleen taken from the hemorrhagic shock group were different from other groups,while the difference of the 7 in- dexes of brain taken from the different groups was not so obvious.The multivarate regression analysis con- formed the result of the univariate analysis.There was some difference of DNA degradation speed between four groups of different manner of death.It might be due to the different degree of congestion and the ca- daver situated in the different conditions.The results of the present study also suggested that the brains were the most stable organ which can be sustained to the influence exerted by the different condition,while the spleens less stable.