Lycium barbarum extract can enhance functional recovery after decompression in a preclinical rat model of cervical spondylotic myelopathy

Abstract

Objectives: While surgical decompression can arrest progression of cervical spondylotic myelopathy (CSM), most patients are left with significant residual neurological deficit and functional impairment. Lycium barbarum polysaccharide (LBP), also known as wolfberry, is a traditional Chinese herb that has been shown to modulate M1/M2 macrophage polarization in acute spinal cord injury with neuroprotection. We hypothesized that Lycium barbarum extract can enhance functional recovery after surgical decompression in an animal model of CSM. Methods: The spinal cords of female Sprague-Dawley rats were slowly and progressively compressed by the introduction of a water-absorbing polymer under the C5 lamina. At 2 weeks post-surgery when all animals were confirmed to suffer from CSM by neurobehavioral studies, rats were randomly allocated into the following experimental groups: (1) LBP alone, (2) decompression alone, (3) decompression with LBP, (4) no treatment, and (5) sham group (no compression). Decompression was performed at 4 weeks post-implantation by C5 laminectomy and excision of any extradural pathology. Data were analyzed using analysis of variance analysis. The integrity of the spinal cord was evaluated by electrophysiological studies, neurobehavioral assessments, and histological and immunohistochemical evaluations. Results: All groups had similar degrees of spinal cord injuries as confirmed by electrophysiological studies. At 8 weeks post-surgery, the LBP and decompression group significantly ameliorated the recovery of hindlimb function of rats compared with the decompression only group, as demonstrated by the Basso, Beattie and Bresnahan (BBB) score. Recovery of somatosensory evoked potential and motor evoked potential latency and amplitude were also enhanced in the LBP and decompression group. Transverse sections of the spinal cord stained with Luxel fast blue showed there was decreased vacuolation of myelin and increased density of myelin staining in the LBP and decompression group. These results suggested LBP decreased intramedullary vacuolization and nerve fiber demyelination that might account for enhanced neurological recovery. Conclusions: These results demonstrate for the first time that LBP extracted from the Chinese herbal medicine can enhance neurological and functional recovery in a preclinical model of CSM. These results form the basis of a randomized clinical trial to examine the synergistic effects of surgical decompression and LBP in CSM patients.