Implication of BDNF expression in transected spinal cord of rats

Objective To explore the change of brain derived neurotrophic factor(BDNF) expression and its relationship with the neurological behavior after spinal cord transection(SCT) in rats.Methods 66 adult SD rats were assigned randomly to sham operation group and SCT group. Rats in SCT group were subjected T_10-T_11 spinal cord transection and allowed to survived 1 d,3 d,7 d,14 d,21 d and 28 d.BBB scores in hindlimbs were observed at 0,7,14,21 and 28 days post operation(dpo).The BDNF expression was determined by using ELISA(28 d) and RT-PCR(each time point) techniques.The localization of BDNF and its mRNA at sham and 28 d after SCT was also observed by immunohistochemistry and in situ hybridization.Results After SCT,the motor function in hindlimbs disappear immediately.The BBB scores get a gradual recovery from 14 dpo to 28 dpo,when compared with that of former timepoint(P0.05).BDNF and its mRNA were located in cytoplasma and neurites. The level of BDNF mRNA(indicated by RT-PCR) was upregulated at 14 days after SCT than that in 1 and 3 dpo(P0.05).The contents of BDNF in the injuried spinal cords at 28 dpo were increased than that in the sham operation group(P0.05).Conclusion Neuroplasticcity has occurred in rats subjected to SCT,and the mechanism may be involved in the increase of BDNF expression in the spinal cord with the time going.