Isolation and characterization of synovial cells from the human temporomandibular joint.

BACKGROUND

The synovial tissues with temporomandibular disorders (TMDs) often show chronic inflammatory changes and the synovial cells participate in the pathogenic processes of TMDs. The synovial membrane is composed of a synovial lining layer and a connective sublining layer. The synovial lining layer is made up of two kinds of cells: macrophage-like type A and fibroblastic type B cells. The aim of this study was to isolate and characterize synovial cells from the human temporomandibular joint (TMJ).

METHODS

Synovial cells were isolated using an explant culture method. Then, we characterized the cultured synovial cells (SGA2 cells) using immunocytochemistry.

RESULTS

SGA2 cells expressed the fibroblastic markers vimentin and prolyl 4-hydroxylase; they also expressed laminin and heat shock protein 27, all of which are markers of type B cells. However, some cells expressed the macrophage marker CD68. These CD68-positive cells simultaneously expressed laminin.

CONCLUSIONS

We isolated and cultured synovial type B cells from the human TMJ, and identified the presence of intermediate type synovial lining cells, having the phenotypic properties of both type A and type B cells, among the synovial lining cells.