Translational validity of quantitative sensory testing in chronic pain neuro-sensitization: guide of use and interpretation in osteoarthritis animal models

Chronic osteoarthritis (OA) pain is a complex nociplastic condition that affects humans, as well as cats and dogs. This review summarizes the physiology of pain in healthy individuals, the physiopathology of OA pain, and the use of quantitative sensory testing (QST) to objectively assess somatosensory sensitization associated with chronic OA pain. It discusses the translation of human OA pain phenotype profiles to animals, the management of neuro-sensitization with currently prescribed treatments, and complementary methods for evaluating neuro-sensitization, such as electrodiagnostic testing. Additionally, this review serves as a practical guide for standardizing QST in rats, cats, and dogs, with explanatory appendices. It was hypothesized that in translational comparison with the human condition, OA-induced rat models and naturally occurring OA in cats and dogs would exhibit similar somatosensory sensitization profiles. As observed in human OA, an imbalance between facilitatory and inhibitory endogenous controls is also evident in animal OA. This dysregulation can be characterized using QST and underlies the distinct nociceptive phenotypes. Confirming and validating OA pain profiles will promote a patient-tailored approach to effectively alleviate neuro-sensitization in humans and animals.