Analgesic Effect of Dizocine Combined with Ropivacaine on Recurrent Neuropathic Pain in Peripheral Nerve Compression Rats

To explore the analgesic effect of dizocine combined with ropivacaine on recurrent neuropathic pain in rat model of peripheral nerve compression. Rats were randomly divided into 5 groups: sham control group (S), peripheral nerve compression model group (M), dizocine group (D), ropivacaine group (R), and combined drug group (DR). Rat peripheral nerve compression model was constructed to observe the symptoms of the rats before and after surgery. Mechanical withdrawal threshold was measured on the 21st day after surgery. The electrophysiological changes of rat peripheral nerve were measured by biopotential recording system, including proximal latency, distal latency, and compound muscle action potential. The incubation period and nerve conduction velocity were further obtained. Histological changes were observed by HE staining and toluidine blue staining. Axon number and myelin damage grade were performed, and the ultrastructure was observed by transmission electron microscopy (TEM). The mechanical withdrawal threshold, nerve conduction velocity, and compound muscle action potential were effectively increased in combination group. However, the proximal latency, distal latency, and incubation period were significantly reduced. Furthermore, dizocine combined with ropivacaine can effectively reduce the degree of myelination. TEM shown that the DR group had the best therapeutic effect, and the histological appearance of the cross section was quite similar to that of the S group. Dizocine combined with ropivacaine has a significant analgesic effect in rat model of peripheral nerve compression.