Expression Of S100B Protein In Rats With Experimental Brain Contusion And Its Significance Of Forensic Medicine

Background and Objective: The estimation of injury interval remains to be a very complex problem in forensic pathology.Although lots of indexes were used to measure the injury interval,no standard was satisfied, especially in case of brain injury.Currently, the injury interval was estimated according to multiple factors. Brain contusion is a common type of injury in forensic pathology, which results in a series of changes in many proteins and cytokines. S100B is a specific marker of neuroglia cell. The expression of S100B protein is related to the extent and severity of damages in central nervous system. S100B may also participate in the pathophysiological processes of brain contusion. To detect the expression of S100B protein in experimental contusion brain in rats has important significance for estimating the injury interval.Methods:(1)Material: Eighty SD rats (from Chong Qing University of Medical Sciences Experimental Animal Center) were divided into experimental group, Negative control group and normal control group randomly. The model of local moderate brain contusion was established by the free-falling-body impact device according to the Feeney method. (2)The samples surrounding the lesion were harvested at different time points.(3)The brain tissue of paraffin wax slices were prepared for HE staining and microscope observation.(4)The expression of S100B protein at different time were detected by immunohistochemical technique.(5)The results were analyzed by SPSS 11.0 software.Results: Four to twelve hours after brain contusion, weak expression of S100B protein in surrounding glial cells can be detected. One day after injury, expression of S100B protein in glial cells began to increase. Three to five days after injury, strong expression of S100B protein in the glial cells can be detected around injury site. After that, the expression intensity gradually decreased. Ten days after injury, there was no significance between experimental group and Negative control group.Conclusion:After brain contusion, the expression of S100B protein varied regularly. The expression of S100B protein increased immediately after injury, then reached to a peak at three days after injury, finally decreased. The level of S100B protein can be used as a supplement index to estimate postmortem interval in brain contusion.