抄録
Leukotriene (LT) C4 in the synovial fluid of patient with osteoarthritis deformans (OA) and rheumatoid arthritis (RA) was measured by radioimmunoassay after its extraction with Sep-Pak C18 cartridge. The amounts of immunoreactive LTC4 (i-LTC4) in samples from patients with OA and RA were not significantly different, being 0.198±0.018 pmol/ml (n=11) and 0.179±0. 016 pmol/ml (n=12), respectively. By high performance liquid chromatography and radioimmunoassay, the levels of other sulfidopeptide LTs, such as LTD4 and LTE4, in synovial fluid from patients with RA were found to be significantly higher than those in fluid from patients with OA. The leukocyte number in synovial fluids was not correlated with the i-LTC4 level.
The metabolic activities of these synovial fluids were determined by incubating them with 3H-LTC4 and then separating sulfidopeptide LTs by high performance liquid chromatography. LTC4 was found to be converted by γ-glutamyltranspeptidase activities to LTD4 which was further metabolized by dipeptidase of synovial fluid to LTE4. The conversion of LTC4 to LTD4 in synovial fluids of patients with OA and RA were similar, but the dipeptidase activity converting LTD4 to LTE4 was higher in fluid from patients with RA. It is suggested that a high level of LTE4 may play cause exudation of synovial fluid, since LTE4 has a strong effect in increasing vascular permeability.
