A new rat model of diffuse axonal injury and the injury mechanism

Objective To develop a clinically-relevant model of diffuse axonal injury(DAI),a new rat model of DAI was established by combining linear and angular accelerations and the injury mechanism was explored.Methods According to the combined injury mechanism,an experimental facility was designed.This model let rat rotate 90 degrees after undergoing an impact by dropping a 450 g weight from a height of 0.9 m.The maximum of rotational acceleration was 1.36×105 rad/s2 and rotating time was about 34 ms.Behavioral and pathologic changes of the rats were evaluated.Results Following injury,experimental rats took longer to regain consciousness(11.9±3.6)min than control rats[(6.5±1.3)min,P ＜ 0.01].Behavioral and pathologic observations showed rats conformed to the characteristics of mederate/severe DAI.Conclusion This experimental facility can reproduce DAI with mild levels of both forms of acceleration combined.Its repeatability and stability are good. Key words: Axonal injury; Model; animal