〔Abstract〕 Objective To investigate the role of nucleotidebinding oligomerization domain-like receptor protein 3(NLRP3) inflammasome in hyperalgesia induced by temporomandibular joint osteoarthritis(TMJOA) in rats.Methods Twenty 6-week-old male SD rats were randomly divided into NS group and MIA group. The rat model of TMJOA was established by injection monosodium iodoacetate(MIA) into the upper cavity of temporomandibular joint(TMJ). The changes of pain threshold in the TMJ region of rats after MIA injection were detected by Von Frey. The changes of condyle structure were observed by Hematoxylin-eosin(HE) and Safranin O-fast green stains. Histopathological changes of trigeminal ganglion(TG) were observed by HE stains. The expression and distribution of TG NLRP3 protein were detected by immunohistochemistry. Western blot was used to detect the protein levels of NLRP3 and interleukin(IL)-1β in TG. The mRNA levels of NLRP3,apoptosis-associated speck-like protein(ASC),cysteinyl aspartate specific proteinase(Caspase-1),IL-1β and IL-18 in TG were detected by quantitative real-time polymerase chain reaction(qRT-PCR). Results Compared to saline group,the pain threshold of experimental TMJ osteoarthritis rats decreased(P<0.05). TMJ and TG showed obvious pathological changes. The protein and mRNA levels of NLRP3 expressed in the tissues of rats in the TMJOA group increased(P<0.05).Conclusion NLRP3 inflammasome may be involved in the regulation of hyperalgesia in TMJOA rats.