Objective: To investigate the effects of Gegen Dingxuan capsule on behavior, X-ray signs of the cervical spine, and levels of norepinephrine (NE), nitric oxide (NO), endothelin (ET-1), and calcitonin gene-related peptide (CGRP) in the plasma of a rat model of cervical vertigo and additionally to clarify the underlying mechanisms of action.
Method: A total of 40 male SPF Sprague-Dawley rats were randomly assigned to blank control, model, Sibelium, and Gegen Dingxuan capsule groups, with 10 rats in each group. A rat model of cervical vertigo was produced by physically damaging the cervical spine, thereby perturbing its stability. After cervical spine surgery, rats in the Sibelium and Gegen Dingxuan capsule groups were administered Sibelium and Gegen Dingxuan capsule, respectively. After 4 and 8 weeks of administration, balance beam test was used to assess behavior, lateral X-ray images of the cervical spine were taken and scored, and the plasma levels of NE, NO, ET-1, and CGRP were measured.
Results: After 4 and 8 weeks of drug administration, the balance beam test scores in the Gegen Dingxuan capsule group were significantly higher than those in the Sibelium group. The radiographic scores were significantly lower in the Gegen Dingxuan capsule group than those in the Sibelium group at 8 weeks. Plasma NE, NO, ET-1 levels, and ET-1/CGRP ratio were significantly decreased in the Gegen Dingxuan capsule group compared with the model group. No significant difference was found between the Sibelium and Gegen Dingxuan capsule groups. Plasma CGRP levels were significantly increased in the Gegen Dingxuan capsule group compared with the model group and were significantly decreased compared with the Sibelium group.
Conclusions: Gegen Dingxuan capsule improves behavior, radiographic scores, reduces plasma levels of NE, NO, ET-1, and the ET-1/CGRP ratio, and increases plasma CGRP levels. Gegen Dingxuan capsule may improve outcome in the rat model of cervical vertigo by ameliorating cervical facet joint disorder, relieving cervical muscle spasm and vasospasm, increasing blood supply, and regulating humoral factor levels.