An Experimental Study On Correlation Between PMI And AKP,γ-GT,Fe,P In Vitreous Humor In Rabbits

Objective:To investigate correlation between PMI and alkaline phosphatase (AKP),y-glutamyl transpeptadase(y-GT),iron (Fe),phosphorus (P) in vitreous humor in rabbits after death.To seek a exact method of estimating postmortem interval(PMI).Methods:this study detected the concentration of four elements in the vitreous humor of rabbit at postmortem time intervals of 0,1,2,4,8,12,24,36 and 48 hours in rabbits and explored the relationship between their concentration and PMI by automatic biochemistry analyzer under 25-30℃and 10-15℃. These elements included alkaline phosphatase (AKP),γ-glutamyl transpeptadase(y-GT),iron (Fe),phosphorus (P).We use Person liner-correlation to investigate the correlation between the four element and postmortem interval(PMI).Result:The relationship between PMI and the two enzymes'activity and the concentration of Fe,P under 25-30"C were:AKP(0-48h,r=0.97); r-GT(0-48h,r=0.979); Fe(0-2h,r=0.994); Fe(2h-24h,r=0.923); Fe(24-48h,r=0.97); P(0-48h,r=0.966). The relationship between the two enzymes'activity and the concentration of Fe,P under 10-15℃were:AKP(0-48h,r=0.969); r-GT(0-48h,r=0.959); Fe (0-4h,r=0.965);Fe (4-24h, r=0.904); Fe(24-48h, r=0.973);P(0-48h r= 0.971).Meanwhile, with repeated measurement F-test,we found that two enzymes'activity change and the concentration change of Fe,P have obvious statistical differences in the temperature between25-30℃and 10-15℃respectively (p<0.01).The formulate of the relationship between PMI and the two enzymes'activity and the concentration of Fe,P under 25-30℃is y= 45.62-0.083x (x=AKP y=PMI P<0.01); y= 55.21-0.159x (x=y-GT y=PMI P<0.01); y=-1.243+0.242x (x= Fe y= PMI P<0.01); y= 42.18-3.148x(x=Fe y=PMI P<0.01); y=-2.754+3.396x (x=Fe y=PMI P<0.01);y=-11.386+23.47x (x=P y=PMI P<0.01).The formulate of the relationship between PMI and the two enzymes'activity and the concentration of Fe,P under 10-15℃is:y= 48.32-0.081 x (x=AKP y=PMI P<0.01); y= 60.65-0.170y (x=y-GT y=PMI P<0.01); y=-2.346+0.451 x (x=Fe y=PMI P<0.01); y =38.813-2.629x(x=Fe y=PMI P<0.01); y=-3.26+3.909x.(x=Fe y=PMI P<0.01);y=-10.10+28.19x (x=P y=PMI P<0.01). The stepwise regression analysis formulate of the relationship between PMI and the two enzymes' activity under 25-30℃is y=48.435-0.095x1-0.029x2(xl=AKP x2=y-GT,r=0.989 P<0.01). The stepwise regression analysis formulate of the relationship between PMI and the two enzymes'activity under 10-15℃is y=51.82-0.051x1-0.063x2 (x1=AKP x2=γ-GT y=PMI r=0.944 P<0.01).Conclusion:The concentration of Fe,P,AKPand y-GT in vitreous humor of rabbit at 48 hour after death were related to PMI significantly.The concentration of AKP,γ-GT,Fe及P in vitreous humor of rabbit at hour 48 may be a reference indicator to estinmate PMI.