Abstract: Objective To study the effects of 3-n-butylphthalide (NBP) on motor function and learning and memory ability in rats with diffuse brain injury (DBI). Methods 128 male Sprague-Dawley rats were randomly divided into sham operation group, traumatic group,low-dose NBP treatment group and high-dose NBP treatment group with 32 rats in each group. Every group was divided into 24 h, 48 h and 72 h subgroups. DBI rat model was established according to the description of Marmarou's diffused brain injury. The histopathologic changes of cerebral tissue (0.2 cm bilateralis coronal line) were observed by light and electron microscope at 24 h, 48 h and 72 h after injury. Morris water maze and rolling test were performed daily at 24, 48 and 72 h (time points). Results Compared with the model group, the damage of brain tissue decreased, and the survival nerve cells increased (P<0.01). The behavioral tests showed that the latency to find the platform shortened (P<0.01) and the frequency of crossing the platform increased in the 72 h subgroup (P<0.01). The general movement ability enhanced in NBP groups (P<0.05). All the indexes were more significant in high-dose NBP treatment group. Conclusion NBP can improve neurological function and learning and memory function after brain injury and the molecular mechanisms is related to the decrease of the nerve cells lose and traumatic cerebral ultrastructure damage.

Key words: diffuse brain injury, learning, motor, ultrastructure, rats