Assessment of Knee Hyperalgesia in Mice using Pressure Application Measurement.

Assessment of knee hyperalgesia provides a robust assay for measuring peripheral sensitization in the knee, and represents a clinically relevant pain-dependent behavior that can be used in rodent models of arthritis. Several methods have been reported to determine the threshold for responses to knee compression in rodents. Here, we aimed to adapt existing methods to develop a standardized method for assessing knee hyperalgesia in adult mice, using a Pressure Application Measurement (PAM) device. The protocol includes detailed steps, training recommendations for new experimenters, and tips for achieving consistent results. We provide suggestions for optimal training of a new experimenter. Finally, representative outcomes are provided for both acute models of transient hyperalgesia and experimental osteoarthritis (OA) models, which are characterized by chronic pain. This method is highly sensitive to pharmacological interventions, making it suitable for evaluating the effects of mediators like cytokines and for medium-throughput drug screening assays. In summary, the described approach provides a robust and clinically relevant method for quantifying knee hyperalgesia.