The Relationship Between The Changes Of Magnesium Ion,Phosphorus Ion,Urea,Amylase,α Hydroxybutyrate Dehydrogenase Concentration In Vitreous Fluid Of Male Rats With Different Causes Of Death In Xining Area And The Early Death Time

Objective To investigate the relationship between the change of magnesium ion(Mg²⁺),phosphorus ion(P³⁺),urea,amylase（AMS）αHydroxybutyrate dehydrogenase（α-HBDH）concentration in vitreous humor（VH）of male rats with different causes of death in Xining area and the postmortem interval（PMI）.Methods 105 male SD rats were randomly divided into 3 groups（drowning group,strangulation group and severe blood loss death group）for execution.After being killed,they were placed in a constant temperature and humidity incubator（temperature 14℃,humidity 55%）to simulate the local temperature and humidity of Xining.Each group was further divided into 7 groups according to the time of death（0,3,6,9,12,18,24 hours）,with 5 rats in each group.The 0h group after death（immediately after death）of each group was used as the control group.The constant temperature and humidity incubator（temperature:14℃,humidity:55%,simulating the temperature and humidity of Xining）is uniformly placed.The vitreous fluid was extracted at the set time point in the three death cause groups and 0h in the control group,and Mg²⁺,P³⁺,Urea,AMSα-HBDH concentration.SPSS19.0 statistical software was used for statistical analysis of relevant data.Results The concentration of Mg²⁺increased first and then decreased with the prolongation of PMI（P<0.01）;The concentration of P³⁺in strangulation group and severe blood loss death group increased with the prolongation of PMI,while that in drowning group increased first and then decreased with the prolongation of PMI;The urea concentration increased first and then decreased with the prolongation of PMI（P<0.01）;The concentration of AMS increased first,then decreased,then increased and then decreased with the prolongation of PMI（P<0.01）;The concentration ofα-HBDH increased first,then decreased and then increased with the prolongation of PMI（P<0.05）.Mg²⁺,P³⁺,Urea,AMSα-HBDH concentrations vary.The r²maximum of the cubic regression model of Mg²⁺under drowning conditions,and the regression equation is:（?）=0.089+0.004x-0.001x²+2.936E-005x³;The r²maximum of the cubic regression model of Mg²⁺under strangulation condition,and the regression equation is:（?）=0.062+0.013x-0.001x²+2.410E-005x³;The r²maximum of the cubic regression model of Urea under death due to massive blood loss condition,and the regression equation is:（?）=0.730-0.011x-0.002x²+6.613E-005x³.Conclusion 1.At Xining area,the concentration changes of magnesium ion, phosphorus ion,urea,amylase andα-HBDH in vitreous fluid of male rats with different causes of death are related to early PMI.2.The concentrations of Mg²⁺and Urea in male rats increased first and then decreased with the prolongation of PMI;α-HBDH concentration increased first,then decreased and then increased with PMI prolongation;The concentration of P³⁺under drowning condition increased first and then decreased with the prolongation of PMI,and the concentration of P³⁺under drowning and massive blood loss death is positively correlated with PMI;The concentration of AMS increased first,then decreased,and then increased and then decreased with the prolongation of PMI.3.The cubic regression equations of Mg²⁺,P³⁺and Urea are more suitable for inferring PMI of male rats under drowning conditions;The third regression equation of AMS is more suitable for inferring the PMI of male rats under the condition of severe blood loss death;The third regression equation ofα-HBDH is more suitable for inferring PMI of male rats under drowning and strangulation conditions.