Objective: To investigate changes of brain derived neurotrophic factor (BDNF) expression in neurons in traumatic brain injury (TBI) rats.
Methods: Adult SD rats were divided into sham and operated group resulted from hammer fall contusion (30 cm high, 50 g weight). Thirteen rats in each group were used. Some of animals (n = 6 in each group) were used to perform immunohistochemistry and in situ hybridization, and the other (n = 7) was used for RT-PCR. After NSS assessment was determined at 1, 3, 8, 13 days, TBI rats were sacrificed, brain tissues were then harvested to measure BDNF level. Data were analyzed by using statistic method.
Results: A increased NSS scores (P < 0.05) was observed after TBI, which implied the significant neurobehavioral changes in rats. But a gradual decreasing NSS scores (P < 0.05) was also observed along with time prolonged. Severe neurological severity function was seen following TBI, and it presents a gradual improvement indicated by decreasing NSS scores, despite BDNF mRNA level in whole brain tissue did not present a significant change, the BDNF expression (indicated by optical density values analysis) in subcellular structure, known as neurons, exhibited a significant increase, when compared with that of sham group (P < 0.05). This could simultaneously accompany with the decrease in the number of neurons in TBI rats.
Conclusion: TBI rats exhibit a neuroplasticity with the BDNF upregulation in neurons following injury.