Abstract: Objective To study the expression of S100B and glial fibrillory acidic protein （GFAP） after primary brainstem injury in rat and discuss the changes with brainstern injury time and their mechanism in the injury. Methods The brainstem injury animal model was established using the mechanical impacting method. The HE staining, Gless argentaffin staining and SP immunohistochemical method were applied to observe the changes of S100B and GFAP at different injury time. The immunostaining results were measured statistically with imaging analysis technology. Results A large number of S100B positive cells could be seen in 30 min. Afterward, expression increased gradually with time and peaked up in 24 h, and reversed back the normal in 72 h. The GFAP positive cells showed rise continually in 30 min, and reached the peak in 48 h, then started to decrease, but still higher than that in control. Conclusion The expression of S100B and GFAP is correlated with post traumatic intervals after brainstem injury in rat, and may be useful in estimation post traumatic intervals and nerve regeneration.

Key words: forensic pathology, wounds and injuries, brain stem, S100B, glial fibrillory acidic protein, rats