Immunohistochemical Expression of IL1-R1 in the TMJ Disks

Objectives: The fibrocartilaginous disk in the temporomandibular joint (TMJ) consists of collagen fibers and fibroblast-like cells. It plays an important role in pressure distribution of the TMJ. When a disk is chronically overloaded, it may undergo structural changes that have pathological consequences. Cytokines and their receptors have been shown to be present in the synovial fluid of patients with internal derangement and osteoarthritis. Interlukin 1 (IL-1) acts as a pro-inflammatory cytokine. Most of the IL-1 signal has been shown to be transmitted through . Interlukin 1 type 1 receptor (IL-1R1) in T lymphocytes as well as B lymphocytes and monocytes. In patients with internal derangements, fibroblasts and other cells that are under chronic trauma may release IL-1 as a protective mechanism. It is hypothesized that in TMJ dysfunction, IL-1R1 expression levels may be elevated. The majority of studies have been performed with synovial fluid, animal models or cadavers. Therefore, the objective of this study is to determine the association of IL-1R1 expression in the disks of patients with TMJ dysfunctions using an immunihistochemical approach to evaluate the joint disk.
Methods: A total of 45 human TMJ samples were collected, with 36 samples in the test group (patients with anterior disk displacement with reduction (n=29) and without reduction (7) and nine samples in the control group. The fixed discs were immunostained with IL-1R1 antibodies. They were histochemical analyzed and TMJ disks were statistically compared between the groups (P<0.05).
Results: There was a difference in the expression of immunostained IL-1R1 between the control group and the groups of displacement with and without reduction.
Conclusions: IL1-R1 plays a role in the inflammatory process and degradation of TMJ discs in patients with TMJ dysfunctions.