A novel therapeutic approach of ultrasound stimulation to restore forelimb functions following cervical cord injury in rats

Abstract

Low-intensity pulsed ultrasound (LIPUS) stimulation has shown promising results in neurorehabilitation following a traumatic injury in brain and peripheral nerves. However, the effects of LIPUS stimulation in the injured neural circuit after spinal cord injury (SCI) are still unknown. We investigated the effects of LIPUS on forelimb functions in chronic cervical cord injured rats with and without a serotonergic agonist drug, Buspirone treatment. Twenty-six rats were trained for forelimb reaching and grasping followed by C4 dorsal funiculi crush injury. To deliver LIPUS, a silicon-coated ultrasound disc was implanted above the cervical cord and EMG electrodes were implanted into forelimb muscles. In two cohorts (LIPUS and LIPUS + Buspirone) rats were tested pre-, with- and post-ultrasound stimulation. In LIPUS group rats, fore-limb reaching and grasping success rates first increased and then dropped after 3 weeks while for combination of drug and LIPUS stimulation the score continued to increase. Furthermore, LIPUS stimulation alone did not result in any significant improvement of grip strength compared to the control and combined groups. The findings of this study indicated the potential of LIPUS in SCI recovery and offer a future research direction of a new neuromodulation method.