Treadmill running promotes functional recovery and decreases brain-derived neurotrophic factor mRNA expression following sciatic crushed nerve injury in rats

Aim. Peripheral nerve injuries are commonly encountered clinical problems and often result in severe functional deficits. In the present study, the effects of treadmill running on the recovery rate of locomotor function and the expression of brain-derived neurotrophic factor (BDNF) mRNA following sciatic crushed nerve injury in rats were investigated. Methods. Experimental design: comparative investigation was performed over 14 days. Setting: experimental animal laboratory. Participants: 24 male Sprague-Dawley rats weighing 200±10 g. Animals were randomly assigned into 3 groups: the sham-operation group, the sciatic nerve injury group, and the sciatic nerve injury and running group. Interventions: the right sciatic nerve was crushed for 30 s using a surgical clip. Rats of the running group were made to run on a treadmill for 30 min once a day for 12 consecutive days. Measures: functional recovery was analyzed using a walking track analysis which can be quantified with the sciatic function index (SFI) and BDNF mRNA expression was analyzed using reverse transcription-polymerase chain reaction (RT-PCR). Results. Sciatic crushed nerve injury showed characteristic gait changes showing decrease of SFI value and treadmill running significantly enhanced the SFI value. The level of BDNF mRNA expression was increased following sciatic crushed nerve injury and treadmill running significantly suppressed the sciatic nerve injury-induced increment of BDNF mRNA expression. Conclusion. It can be suggested that treadmill running after peripheral nerve injury is effective in the functional recovery by inhibition on the over-expression of BDNF mRNA.