Expression Of PPARγ、NF-κB And COX-2in A Rat Hepatic Impact Injury And Their Diagnose Value In Forensic Medicine

Objective:To investigate the expression trend of PPARγ、NF-κB and COX-2in rat model of hepatic impact injury and their relation with the wound ages, aimed to provide some help for forensic estimation of wound age.Methods:The54Sprague-Dawley rats were randomly divided into three groups: antemortem group(7subgroups), postmortem group (1subgroup), and control group (1subgroup)with6rats in each subgrouop.The samples were cut respectively at0.5h、1h、2h、4h、8h、12h、24h after hepatic impact injury in the antemortem injury group,and at1h in the postmortem injury group. Free falling body method was used to make the hepatic impact injury model, the expression of PPARy、NF-κB and COX-2in different wound ages was observed and measured quantitatively with Super Vision immunohistochemical staining and MIAS-2000image analysis techniques respectively.Results:(1) The result of HE:Normal trabecular arrangement,normal hepatic morphological structure and no inflammatory cell were detected in the liver of the control group.The liver in the experimental group after hepatic impact injury in rats expressed sinusoidal stretch and congestion,hepatocytes edema degeneration, hepatocyte necrosis.Deeply stained nuclei and condensation of hepatocyte was detected.There were obviously invasion of inflammatory cells,and the structure of hepatic cords was destroyed. (2) The immunohistochemical staining demonstrated that NF-κB showed a low expression in the control hepatocytes, increased at0.5h after hepatic impact injury in rats, and kept increasing with the prolongation of injury time, reached the maximum level at8h with a high level till24h post-injury.The expression of COX-2protein could be detected occasionally in normal hepatocytes of the control group,increased at0.5h after injury and peaked at2h in Kupffer cells, vascular endothelial cells, bile duct endothelial cells and hepatocytes, and then decreased.The expression of PPARy protein could be detected in some hepatocytes at the central vein and portal area of the control group, increased at0.5h after hepatic impact injury in rats, and kept increasing with the prolongation of injury time, reached its peak at4h and then decreased remarkably.The comparison has been made between the antemortem group and the control group, the antemortem group and its previous group, the difference is statistically significant(P<0.05).But there was no statistical significance about the three indexes between the different ages after postmortem injury and the control group(P>0.05).Conclusions:(1) It can be used to authenticate antemortem and postmortem hepatic impact injury by checking out the expression of PPARy、NF-κB and COX-2.(2) Expression of PPARy、NF-κB and COX-2is correlated with posttraumatic intervals after hepatic impact injury in rats, suggesting that the time-dependent changes of PPARy、NF-κB and COX-2in24hours after hepatic trauma could be applied in dating of wound for hepatic impact injury.