Effect of Toll-Like Receptor 4 on Synovial Injury of Temporomandibular Joint in Rats Caused by Occlusal Interference

Synovitis is an important disease that causes intractable pain in TMJ. Some investigations suggested that the increasing expression of IL-1βsecreted by synovial lining cells plays an important role in synovial inflammation and cartilage destruction in TMJ. In our previous research, the results demonstrated that TLR4 is involved in the expression of IL-1βin SFs from TMJ with lipopolysaccharide stimulation. However, the inflammatory response that occurred in synovial membrane is not caused by bacterial infection. In the current study, we investigated whether or not TLR4 participates in the inflammatory responses and the expression of IL-1βin synovial membrane of rats induced by occlusal interference. The results showed that obvious inflammation changes were observed in the synovial membranes and the expression of TLR4 and IL-1βwas increased at both mRNA and protein levels in the occlusal interference rats. In addition, the inflammation reactions and the increased expression of IL-1βcould be restrained by treatment with TAK-242, a blocker of TLR4 signaling. The results prompted us that the activation of TLR4 may be involved in the inflammatory reactions and increased expression of IL-1βin patients with synovitis and participate in the mechanisms of the initiation and development of synovial injury by regulating the expression of inflammatory mediators like IL-1βin synovial membranes.

Facet Cyst Haematoma in the Lumbar Spine: A Report of Four Cases

We present 4 cases of facet cyst haematoma in the ligamentum flavum of the lumbar spine. All patients presented with a one-to-3-month history of back pain or numbness in the legs, and sudden neurological deterioration. One also developed cauda equina syndrome and another developed radiculopathy. In all cases, magnetic resonance imaging showed a mass with high signal intensity on both T1- and T2-weighted images. Facet arthrography and computed tomography revealed communication between the mass and the neighbouring facet joint. The haematomas were removed en bloc with the ligamentum flavum. They were surrounded by the ligament and contained degenerated and lacerated elastic fibres but no synovial lining cells. Facet cyst haematoma is so-named because of bleeding from tissue adjacent to the facet joint into a pre-existing facet cyst.