Abstract: Objective To study the changes of expression of relevant factors in rat brain after concussion injury and to provide scientific basis for forensic estimation of brain injury interval. Methods Brain tissues were sampled from the established SD rat animal model of brain concussion, routinely processed and stained with HE and immunohistochemically stained with antibodies directed against heat shock protein 70 (HSP 70), transforming growth factor beta 1(TGF-β1) and basic fibroblast growth factor(bFGF). The sections were examined under light microscope with IMAGE analytical system and homologous statistical analysis. Results The expression of HSP 70 was observed in 30 minutes after brain injury. The amount of neurons expressing HSP 70 increased gradually, reached its peak at 12 hours and then declined at 24 hours after brain injury. The expression of bFGF was observed 3 hours after injury in brain stem, reached its peak at 12 hours, and then declined. The expression of TGF-β1 was detected 6-24 hours after brain injury, remained at its peak up to 3 days. Conclusion Brain injury can induce a chronological expression of HSP 70, bFGF and TGF-β1. The results can be a potential for estimating the age of brain injury using several markers.

Key words: forensic pathology, brain concussion, HSP 70 heat-shock proteins, transforming growth factor beta1, fibroblast growth factor, wound age estimation, rats