Developing a model of temporomandibular disorder in the common marmoset using nerve growth factor

Abstract

Developing an animal model that more closely represents the human multidimensional pain experience is an important step towards addressing the current chronic pain crisis. The common marmoset has potential as this model species given its biological, neurological and phylogenetic similarity to humans. Here, we developed a model of myofascial temporomandibular disorder (TMD) in the marmoset by injecting nerve growth factor (NGF) into the superficial masseter. Following injection, animals showed reduced mechanical withdrawal thresholds at 5 g and 10 g doses of NGF and changes in circadian rhythm and feeding initiation following injection of 10 g of NGF. Animals did not show evidence of jaw dysfunction, masticatory alterations, or grimace during novel behavioural assays. The model is transient, with pain resolution occurring approximately 7 days after onset, which allows for repeated testing on the same animal. This same NGF-TMD model has been previously validated in rodents and humans and presents an opportunity for forward and reverse translation to examine mechanisms, develop relevant pain assessment tools, and ultimately test novel treatments for TMD and other musculoskeletal pain conditions. New & NoteworthyWe developed a long-lasting but transient ([~]7 days) model of myofascial temporomandibular disorder pain in marmosets. Mechanical hypersensitivity and changes to circadian activity and spontaneous eating behaviours were observed. There was no evidence of jaw dysfunction, altered food preference or changes in grimace. The NGF-TMD model can be translated to the marmoset with the potential for investigating mechanisms and novel interventions for TMD.