A.M.CHOO1, S DAVIS1, A BARBOZA1, M MANZANO1, A HU1, M OSBORNE1, Q CHANG1, E LEAHY1, T HANANIA1
1PsychoGenics Inc., Tarrytown, NY, USA
Clinically, chronic pain and affective disorders often occur as co-morbidities. We studied the development of anxiety in a model of chronic constrictive injury (CCI) to the sciatic nerve in Sprague-Dawley rats. Compared to uninjured animals, CCI rats exhibited sensorimotor deficits such as chronic mechanical allodynia as measured in the von Frey filament test, heighten sensitivity in the cold plate test, as well as motor deficits in the rotarod test. In the NeuroCube system, PGI’s proprietary gait analysis technology, CCI animals show significant discrimination in multivariate analyses of gait, body motion, paw position, rhythmicity and imaging features. CCI animals show reduced paw pressure on the injured hind paw as well as significant deficits in gait features such as speed, stride length, and rhythmic limb coordination. These sensory pain indicators and motor impairments were significantly reduced with gabapentin treatment. CCI animals exhibited reduced open arm time in the elevated plus maze indicative of increased anxiety. These results illustrate that the CCI model of chronic neuropathic pain alters the anxiety phenotype in Sprague-Dawley rats and this model may be useful for assessing the development of affective co-morbidities over time.