Background: Proliferation of synovial cells is considered to play a key rol
e in rheumatoid arthritis (RA). Using paclitaxel, a unique antineoplastic a
gent known to suppress collagen-induced arthritis, we conducted an in vitro
study of cell kinetics on cultured synovial cells from patients with RA.
Methods: Alterations of the cell cycle of cultured fibroblast-like synovial
cells (FLSs) from patients with RA were studied using flow cytometry and l
aser scanning cytometry. Apoptosis and accumulation of cyclin concerning ef
fects of pactitaxel were detected.
Results: Paclitaxel induced arrest of the cell cycle at G(2)/M phase and ap
optosis in FLSs. The late stage of apoptosis was determined by the positivi
ty of terminal deoxynucleotidyl transferase assay. Morphological observatio
n by combined usage of both annexin V and propidium iodide on FLSs on a sli
de glass showed early apoptotic changes in detail. FLSs arrested at G(2)/M
phase showed marked accumulation of cyclin B1. The effects of paclitaxel de
creased on FLSs, which diminished proliferative activity.
Conclusions: These data indicate that paclitaxel induces cell arrest at G(2
)/M phase followed by apoptosis in human FLSs, which have high proliferativ
e activity, and possible therapeutic effects of paclitaxel on RA. Cytometry
44: 349-354, 2001. (C) 2001 Wiley-Liss, Inc.