Abstract: Objective To study the expression of nerve growth factor (NGF) in diffuse axonal injury (DAI) in rat. Methods Eighty SD rats were used and samples were taken at l h, 3 h, 6 h, 12 h, 24 h, 48 h, 3 d, and 7 d after brain injury. The expressions of NGF in cerebral cortex, thalamus, cerebellum, and hippocampus were studied with immunohistochemistry and compared with normal group and sham operation group. Results Low expression of NGF was observed in normal group and sham operation group. The expression of NGF increased 1h after injury, peaked at 12 h, and returned to basal level at day 7. Conclusion NGF is involved in repair of DAI. The changes of NGF expression following DAI may be applied to estimate the post-injury time interval of the brain in forensic medicine.

Key words: forensic pathology, immunohistochemistry, NGF, diffuse axonal injury, injury time