Abstract
Rheumatoid arthritis (RA) is a systemic inflammatory disease with a main symptom of chronic polyarthritis. Migration of T lymphocytes to synovium, which is mediated by the adhesion molecules expressed in both lymphocytes and vascular endothelial cells, play a key role in the synovial imflammation.
To investigate the mechanism of therapeutic effect of low powar laser irradiation to RA Joint, adhesion molecules in synovial tissue were studied.
Nine knee joints of 8 RA cases were irradiated with a Ga-Al-As laser (790nm in wave length and 20mW of output power) at 6 points on the lateral aspect of joint prior to the replacement surgery. Several pieces of synovial tissue from the lateral irradiated area and from the medial nonirradiated area as a control were resected for study at surgical operation. Frozen sections were immunohistochemically studied using monoclonal antibodies to the adhesion molecules. In 5 of 9 knee joints, immunohistochemical studies for adhesion molecules of cultured synovial tissue and ELISA for soluble adhesion molecules in culture fluid were performed. Moreover, in 5 of 9 knees, electron microscopic observation of synovial tissue irradiated with low power laser were carried out.
Expression of ICAM-1, VCAM-1 and fibronectin in the synovial tissue was suppressed in the irradiated area comparing with that in the nonirradiated area. ELAM-1 staining of the endothelial cells was also decreased, although the staining was weak even in nonirradiated area. LFA-1 staining of lymphocytes was markedly decreased in the perivascular area, on the other hand it was almost unchanged in the sublining area of irradiated synovium. Staining of ICAM-1, VCAM-1 and ELAM-1 also decreased in the cultured synovial cells irradiated with low power laser, but soluble adhesion molecules in the culture fluid of synovial cells showed no significant change with low power laser irradiation.
Electron microscopically, markedly dilated rough endoplasmic reticulum of fibroblast like cells and flattening of vascular endothelial cells were observed in the irradiated synovial tissue.
These morphological changes of cells in the synovial tissue irradiated with low power laser would be related to the decreased cytokine production, resulting suppression of adhesion molecule expression and improvement of synovial inflammation.
