A New Animal Model of Brachial Plexus Neuralgia Produced by Injection of Cobra Venom into the Lower Trunk in the Rat

• Published in: Pain medicine (Malden, Mass.) Mass.), 2015-09, Vol.16 (9), p.1680-1689
• Main Authors: Liu, CaiCai, Qian, XiaoYan, JianXiong, AN, Wang, Yong, Fang, QiWu, Jiang, YiDe, Cope, Doris K, Williams, John P.
• Format: Article
• Language: English
• Subjects: Animals; Behavior; Brachial Plexus Animal Model; Brachial Plexus Neuropathies - chemically induced; Brachial Plexus Neuropathies - complications; Brachial Plexus Neuropathies - pathology; Disease Models, Animal; Elapid Venoms - toxicity; Hyperalgesia - chemically induced; Hyperalgesia - pathology; Male; Mechanical Hyperalgesia; Microscopy, Electron, Transmission; Neuralgia - chemically induced; Neuralgia - pathology; Neuropathic Pain; Pregabalin; Rats; Rats, Sprague-Dawley; Rodents; Ultrastructural Alterations; Venom
• ISSN: 1526-2375; 1526-4637
• DOI: 10.1111/pme.12722

Background To establish a new animal model for the study of neuropathic pain developed by administration of cobra venom to the brachial plexus (BP) lower trunk. Methods Fifty‐eight adult male Sprague‐Dawley rats were randomly divided into 5 groups. Under pentobarbital sodium anesthesia, cobra venom was injected into the lower trunk or sham operation was performed in the animals. On postoperative day 1 and day 12, pregabalin was administered intragastricly at 30 mg/kg in two groups. Mechanical withdrawal thresholds (MWT) were tested with von Frey filaments. Video recordings were used to analyze the spontaneous behaviors. Meanwhile, our model was confirmed by observing ultrastructural alterations of the BP and cervical cord (C8‐T1) via electron microscope examination. Results In comparison to the blank and sham‐operated group, cobra venom‐treated rats showed a profound decrease in the MWT, exploratory and increase in grooming behaviors (P0.05), compared with the control and sham‐operated groups. In pregabalin test POD12 group, the decreased MWT and the increased grooming behavior were improved at 20 days after operation. However, pregabalin had no effect on exploratory activity. Results indicate that pregabalin effectively attenuates mechanical hyperalgesia in acute period. Conclusions The cobra venom model can be used as a model to induce neuropathic pain and to enable study of the mechanism and treatment.