Use of Rat Grimace Scale in Pain Research

Since its introduction in 2011, the rat grimace scale has become a valuable tool for pain assessment in preclinical studies. In our article, we provide an overview of a variety of studies in which this method has been applied in surgical and postoperative pain models, inflammatory pain models, orthodontic and orofacial pain models, neuropathic pain, and others. In addition, we present the results of pain assessment in rats with nitroglycerin-induced migraine. Although the scale covers four functional units, our findings suggest that orbital tightening is preferred in the migraine model as the functional unit that best fits the features of this model. An interesting direction is the prospect of using artificial intelligence technologies for automatic pain grimace recognition and data analysis. This innovative approach promises to significantly reduce the time and resource costs of image evaluation, and improve the accuracy of the estimates by eliminating the subjectivity associated with human evaluations.