Low-energy extracorporeal shock wave therapy promotes BDNF expression and improves functional recovery after spinal cord injury in rats

Low-energy extracorporeal shock wave therapy (ESWT) has been used to treat various human diseases. Previous studies have shown that low-energy ESWT promotes the release of various cell growth factors and trophic factors from the cells surrounding the target lesion. The aim of the current study was to determine whether the application of low-energy ESWT upregulates the expression of brain-derived neurotrophic factor (BDNF) and reduces neural tissue damage and functional impairment using a rat model of thoracic spinal cord contusion injury. We found that low-energy ESWT promoted BDNF expression in the damaged neural tissue. The expression of BDNF was increased in various neural cells at the lesion. Additionally, low-energy ESWT increased the area of spared white matter and the number of oligodendrocytes in the injured spinal cord compared with untreated control animals. There were more axonal fibers around the injured site after the application of low-energy ESWT than control. Importantly, low-energy ESWT improved the locomotor functions evaluated by both the BBB scale and ladder rung walking test in addition to the sensory function measured using a von Frey test. Moreover, the electrophysiological assessment confirmed that the conductivity of the central motor pathway in the injured spinal cord was restored by low-energy ESWT. These findings indicate that low-energy ESWT promotes BDNF expression at the lesion site and reduces the neural tissue damage and functional impairment following spinal cord injury. Our results support the potential application of low-energy ESWT as a novel therapeutic strategy for treating spinal cord injury.