Study Of Postmortem Redistribution Of MA In Rabbits

Postmortem redistribution (PMR) refers to the process of poisons (drugs) diffusing among tissues, organs and body fluids after death. Due to this phenomenon, the concentrations of poisons (drugs) would be different in the specimens collected at different time points after death. Therefore, the reliability of the traditional specimen collection methods is questionable. Many factors could affect the process of PMR, which concludes diffusion along a concentration gradient, the flow of blood after death, dynamic process of toxicant metabolism, postmortem decomposition, and so on. Several factors would participate in the PMR of a certain poison in vivo. Methamphetamine (MA) abuse is very common and frequently leads to poisoning or/and death. Meanwhile, MA might exhibit PMR.Object This study aims to propose a sensitive extraction and detection method of MA, further to explore the PMR of MA in rabbits. The results would be helpful in those cases relating to MA.Methods Thirty study rabbits were randomly divided into six groups. Then the amount of MA solution 30mg/kg by intragastric administrated into 1~4 groups, and 60mg/ml of MA ethanol solution by intragastric administrated into5, 6 groups, respectively. Those rabbits were killed by suffocation, and kept at 15℃environmental conditions in supine position. Samples including cardiac blood, peripheral blood, urine, liver, lungs and brain tissue were collected at 0h, 6h, 24h, 48h in 1~-4 groups and at 6h, 48h in 5,6 groups, respectively.MA concentrations were detected by SPME-GC-MS in different body fluids and tissues of rabbits. 100μm polydimethylsiloxane fibers were used to extract MA, and 1- naphthylamine as an internal standard. The products were detected with the GC-MS selected ion monitoring method. SPSS13.0 software was used for ANOVA, varied the number of multiple comparisons were t test.Results Our results showed that PMR of MA occurred quickly in acute poisoned rabbits. MA concentrations increased in cardiac blood, peripheral blood and liver during 0h~48h after death (P<0.01), but increased first and decreased then in lung tissues (P<0.05). MA concentration decreased lightly in urine (P<0.05). Meanwhile, there was no obvious change in brain tissue (P>0.05). In the presence of ethanol, MA concentrations increased in cardiac blood and liver in 6h and 48h after death(P<0.01), PMR exhibited more obvious in cardiac blood and liver than MA group.Conclusion1. A sensitive extraction and detection method of SPME-GC-MS to MA in biological samples was set up.2. Postmortem redistribution was found that MA concentrations varied in body fluids and tissues of acute poisoned rabbits at different time points after death, there was no obvious change in brain tissue.3. PMR should not be neglected when MA concentration immediately after death was detected.