IL-37b Alleviates Inflammation In The Temporomandibular Joint Cartilage Via IL-1R8 Pathway

Objectives: Interleukin(IL)-37 is a natural suppressor of innate inflammation.This study was conducted to explore the anti-inflammatory effects of IL-37 in temporomandibular joint(TMJ)inflammation.Materials and Methods: The expression of IL-37 in the TMJ was measured using ELISA and IHC.Human TMJ chondrocytes were treated with IL-37b and IL-1?,and inflammation-related factors were detected.siRNA-IL-1R8 was transfected into chondrocytes,and the affected pathways were detected.IL-37b was used in disc-perforation-induced TMJ inflammation in SD rats.Micro-CT,IHC,real-time PCR and histological staining were used to quantify the therapeutic effect of IL-37b.Results: IL-37 was expressed in the synovium and the disc of patients with osteoarthritis(OA)and in the articular cartilage of condylar fracture patients.IL-37 was highly expressed in synovial fluid of patients with synovitis than in those with OA and disc displacement.In vitro,IL-37b suppressed the expression of pro-inflammatory factors.In addition,IL-37bexerted anti-inflammatory effects via IL-1R8 by inhibiting the p38,ERK,JNK and NF-?B activation,while silencing IL-1R8 led to inflammation and upregulation of these signals.In disc-perforation-induced TMJ inflammation in SD rats,IL-37b suppressed inflammation and inhibited osteoclast formation to protect against TMJ.Conclusions: IL-37b may be a novel therapeutic agent for TMJ inflammation.