Objective : The study aimed to establish a novel animal model for trigeminal neuropathic pain following compression of the trigeminal nerve root, and estimate it on the ethology and pathology change.

Methods : 20 adult male Sprague-Dawley rats (200–220 g) were randomly divided into 2 groups: one group ( n = 10) that received chronic compression of the trigeminal nerve root and another group ( n = 10) that received sham operation without compression. Under anesthesia, the rats were mounted onto a stereotaxic frame and injections of a 4% agar solution (10 l) were given to achieve compression of the trigeminal nerve root. A sham operation was performed using identical procedures but injected normal saline instead. Nociceptive behavior was examined 3 days before and then at 3, 9, 15, 30, 40 and 60 days postoperatively. Pathologic changes of the trigeminal nerve root were performed at last. Results : Mechanical hyperalgesia and hypersensitivity persisted until 40 days following compression. The compression produced focal demyelination in the trigeminal nerve root.

Conclusions : The study suggest that prolonged nociceptive behavior following compression of the trigeminal nerve root may mimic trigeminal neuralgia in this animal model and the pathologic changes of the trigeminal nerve root in rats were similar to that in human.