Abstract: Objective To study the expressions of GFAP and S100 in astrocytes after experimental cerebral contusion and role of astrocytes in repairing injury. Methods After established model of experimental focal cerebral contusion in rats, immunohistochemical method was applied to observe the staining changes of glial fibrillary acidic protein (GFAP) and S100. The immunostaining results were measured quantitatively with computer imaging analysis system. Results (1) At 1h after injury, GFAP positive astrocytes around the wounded area were detected. The intensity and GFAP positive cells increased following the post-traumatic intervals and remained higher than normal at 14 d after severe brain contusion. (2) At 12 h after injury, the S100 staining cells were noted, the intensity and S100 positive cells gradually increased following the positive-traumatic intervals, reached a peak at 5 d and then decreased, but still higher than normal. Conclusion expressions of GFAP and S100 in astrocytes are correlated with post-traumatic intervals after cerebral contusion in rats, and may be useful to estimate post-traumatic intervals.

Key words: cerebral contusion, injury time, immunohistochemistry, GFAP, S100