Abstract: Objective To investigate the expressions of hypoxia induced factor-1α(HIF-1α) and insulin-like growth factor-1 (IGF-1) at different post brain injury intervals after cerebral contusion. Methods An experimental rat model of severe cerebral contusion was used and the expressions of HIF-1α and IGF-1 proteins at different post brain injury intervals were studied with immunohistochemistry and imaging analysis technique. Results The expressions of both the HIF-1α and IGF-1 proteins were detected in neurons and glial cells in cerebral cortex, brain stem, and hippocampus. The expression level of HIF-1α started to increase in the neural cells around the injured areas at 2 hours, reached its maximal level at 24 hours, and returned to its baseline level at 14 days after the injury. The expression level of IGF-1 protein started to increase at 6 hours, reached its maximal level at 3 days, and returned to its baseline level at 14 days after the injury. Conclusion The level changes of post injury HIF-1α and IGF-1 expressions in rats may be used for estimation of post brain contusion interval.

Key words: hypoxia inducible factor-1α, insulin-like growth factor-1, forensic medicine, post brain injury interval