Mechanical Quantitative Sensory Testing in A Canine Translational Model of Neuropathic Pain: A Pilot Investigation

Introduction: Drug development related to neuropathic pain is inefficient, related at least in part to limited predictive value of experimental models. The utility of pet dogs with spontaneous disease for use as clinical translational models has recently become a focus. Syringohydromyelia (SM) is a painful spontaneous neurological disorder common in pet dogs of the Cavalier King Charles Spaniel (CKCS) breed which results in behaviours that have long been suggested by veterinarians to represent a neuropathic pain phenotype.

Materials and Methods: Mechanical quantitative sensory testing was performed using an electronic von Frey anesthesiometer in normal CKCS (n = 9) and CKCS with syringomyelia (SM) (n = 7). We hypothesized that dogs with SM would have significantly lower mechanical sensory threshold (ST) than dogs without SM, consistent with hyperesthesia and a neuropathic pain phenotype.

Results: Mean sensory threshold (ST) for normal CKCS was 220.4 ± 42.5 g for the thoracic limbs and 175.6 ± 21.5 g for the pelvic limbs. Mean ST for SM-affected CKCS was 148.8 ± 21.1 g for the thoracic limbs and 129.2 ± 8.2 g for the pelvic limbs. There was a statistically significant decrease in ST in the pelvic limbs of SM-affected CKCS compared with normal (p = 0.045). This relationship was also present in the thoracic limbs but did not achieve statistical significance (p = 0.094).

Discussion: Spontaneously occurring SM in pet CKCS may represent a valuable clinical animal model through which to study interventions aimed at improving treatment of neuropathic pain.

Acknowledgments: No proprietary interest or funding was provided for this project.