Progress of researches on involvement of corticospinal tract in the effect of acupuncture on improvement of post-stroke motor dysfunction

Abstract

The corticospinal tract (CST), descending from the frontoparietal cortex and traveling down to terminate at the anterior horn of the spinal cord to mediate voluntary movements, is frequently injured from the infarcted or hemorrhagic cerebrovascular insults due to stroke. Under the circumstances, motor dysfunction seriously affects the patient's quality of life. Acupuncture therapy has a sequelae, especially in improving motor deficits. In the present paper, we reviewed the current development of researches on acupuncture treatment of poststroke motor dysfunction and its biological mechanisms from 1) delaying patients' development of neuronal degeneration and white matter fibrosis (Wallerian degeneration), 2) improving patients' upper limb motor function and daily life ability by promoting the repair of white matter tracts and CST on the affected side, 3) promoting the compensation of CST on the healthy side, 4) reconstructing the motor conduction pathway to strengthen the bilateral brain connection in ex-perimental animals, and 5) strengthening the sprouting of the contralateral CST to dominate the affected side again across the midline. In addition, acupuncture stimulation induced improvement of axonal rewiring for corticospinal innervation is also possibly related to its functions in accelerating the synthesis and release of neurotrophic factors, down-regulating Nogo-A/RhoA signaling and activating vascular epithelial growth factor/Dll4/Notch signaling pathways.