大鼠死后心肌和肺脏微管蛋白降解规律的初探研究

目的探讨大鼠死后心肌和肺脏微管蛋白（tubulin）的降解规律与死亡时间（PMI）的关系。方法大鼠经切断股动脉致失血性休克处死后，置于RXZ智能型人工气候箱内，实验条件设定为：20℃恒温，湿度50％。分别于大鼠死后0、1、2、3、5和7d时剖取心肌和肺脏组织，应用Western-Blot法检测心肌和肺脏tubulin的含量，并对所得数据进行统计学分析。结果Tubulin在正常大鼠心肌和肺内高表达，死后1d时其含量已开始下降，至死后7d时仍可检测到微管蛋白的存在，但tubulin在肺脏内的降解速度快于心肌。两种组织内tubulin含量随PMI变化的回归方程及相关系数分别为：心肌Y=-1726．Ix＋14083，r=0．9684；肺脏Y=-1439．89x＋12041，r=0．9808。结论大鼠死后心肌和肺脏tubulin的含量逐渐减少，与PMI具有相关性。

A study on the relationship between the degradation of tubulin in cardiac muscle and lung of rat and the postmortem interval

Objective To observe the degradation pattern of tubulin in the cardiac muscle and lung tissue of rats after death.Methods 24 young male Sprague-Dawley rats were divided into 6 groups averagely.After being killed by bleeding,the rats were kept in an artificial climate incubator;the experimental temperature was kept at 20℃ and humidity at 50%.Proteins in cardiac muscle and lung tissue were extracted and tubulin was then examined by Western blot.Thereafter,the semi-quantitative analysis of the Western blot images was performed.Results Tubulin can be detected in the normal cardiac muscle and lung tissue of rats.After 1d postmortem,the tubulin content in these tissues began to decline,and it might still be detected at 7d postmortem,but the tubulin content in lung decreased faster than that in cardiac muscle.A linear relationship between tubulin content in cardiac muscle and lung of rats and the postmortem interval was determined.The linear regression equations and coefficients for integral optic density in relation to PMI were y=-1726.1x+14083 with correlative coefficient r=0.9684 for cardiac muscle and y=-1439.89x+12041 with correlative coefficient r=0.9808 for lung,respectively.Conclusion The level of tubulin in cardiac muscle and lung tissue of rats varied with PMI and the time dependent degradation of this protein was potentially useful for the PMI estimation.