Abstract: Objective To study the alteration of basic fibroblast growth factor(bFGF) expression in astrocytes in vitro after mechanical injury and to understand the repair mechanism of brain injury.Methods Astrocytes were isolated from cerebral cortex of SD rats born in 24 hours,and then cultured and purified.The cultured astrocytes were randomly divided into control group and injury groups that were subjected to mechanical injury at 30 min,1 h,3 h,6 h,12 h,24 h,3 d and 7 d.The levels of bFGF expression in the astrocytes after injury were detected by ABC immunohistochemistry.Results More than 95% of the cultured cells were as-trocytes.The levels of bFGF expression were very low in the control group.On the other hand,increased levels of bFGF expression could be observed at 1-3 h after injury.The expression levels increased significantly at 6-12 h,reached peak level at 24 h,remained at the high level up to 3 days,and then decreased gradually.Conclusion The changes of bFGF expression levels in cultured astrocytes in vitro after mechanical injury are similar to that observed in vivo experimental model,both of which show time-dependent characteristic,with only slightly earlier expression of bFGF observed in vitro.Thus,the expression of bFGF after injury can be one of evidences for estimation of brain injury intervals.The cell injury model in vitro may have superiority in the study of the molecule mechanism of tissue and cell injury.

Key words: forensic pathology, brain injuries, astrocyte, basic fibroblast growth factor, rats