Cognitive effects of electro-acupuncture and pregabalin in a trigeminal neuralgia rat model induced by cobra venom

OBJECTIVE: The objective of this study was to investigate the effects of electro-acupuncture (EA) and pregabalin on cognition impairment induced by chronic trigeminal neuralgia (TN) in rats. DESIGN: Controlled animal study. SETTING: Department of Anesthesiology, Pain Medicine and Critical Care Medicine, Aviation General Hospital of China Medical University. SUBJECTS: Forty adult male Sprague Dawley rats. METHODS: Rats were randomly divided into four groups. The TN model was induced by administration of cobra venom to the left infraorbital nerve. On postoperative day 14, either EA or pregabalin was administered, free behavioral activities were observed. Spatial learning and memory abilities were determined in the Morris water maze. The ultrastructural alterations of the Gasserian ganglion, medulla oblongata and hippocampus were examined by electron microscopy. The changes on long-term potentiation were investigated. RESULTS: After treatment, the exploratory behavior increased and the grooming behavior decreased (P<0.05) for the EA group and pregabalin group compared with the cobra venom group; moreover, demyelination of neurons in Gasserian ganglion and medulla oblongata was reversed. The number of platform site crossings, the average percentages of time in the target quadrant and the field excitatory postsynaptic potential slopes increased (P<0.05) in the EA group compared to the cobra venom group. However, the pregabalin group showed no differences compared to the cobra venom group (P>0.05). Vacuolar degeneration in the hippocampal neurons was mild in the EA group, while it was severe in the pregabalin group. CONCLUSION: EA and pregabalin could alleviate TN induced by cobra venom. EA could also inhibit the cognition deficit induced by TN, while pregabalin could not.