To investigate the longterm effects (12 days) of nonsteroidal antiinflammatory drugs [NSAID: aceclofenac (ACECLO), sodium diclofenac (DICLO), indomethacin (INDO), nimesulide (NIM), rofecoxib (ROFE), celecoxib (CELE), piroxicam (PIROX), and ibuprofen (IBUP)] on the metabolism of human chondrocytes cultured in alginate beads.
Enzymatically isolated osteoarthritic (OA) chondrocytes were cultured in alginate beads in a well defined culture medium for 12 days. The DNA content was measured according to a fluorimetric method and cell proliferation was determined by the incorporation of 3H-thymidine in the newly synthesized DNA. Interleukin 6 (IL-6) and IL-8, stromelysin [matrix metalloproteinase-3 (MMP-3)], and aggrecan (AGG) production were assayed by specific enzyme amplified sensitivity immunoassays, and prostaglandin E2 (PGE2) production by specific radioimmunoassay. All NSAID were tested at the mean peak plasma concentration (Cmax) obtained after oral administration of a therapeutic dose.
In alginate beads, chondrocytes synthesized high amounts of AGG, which were largely (98%) immobilized in the alginate matrix. A large amount (43%) of the IL-8 produced was stored in the alginate beads, whereas almost all IL-6 production (94%) was released in the culture supernatant. At the therapeutic concentration, all NSAID tested fully blocked PGE2 production. ACECLO, DICLO, INDO, NIM significantly inhibited basal and IL-1beta stimulated IL-6 production; CELE and IBUP only inhibited IL-1beta stimulated IL-6 production; and ROFE and PIROX had no significant effects. No NSAID showed significant effects on basal and IL-1beta stimulated IL-8 production, except CELE and IBUP, which slightly increased basal IL-8 production. ACECLO and INDO increased AGG content by 25% in the alginate beads, while the other NSAID were without significant effect. No NSAID were able to modify the inhibitory effect of IL-1beta on AGG production. NSAID did not modify MMP-3 production.
The mechanism of action of NSAID seems to be multifactorial and not limited to the inhibition of cyclooxygenases. Further, in our culture conditions, at the Cmax and by comparison with other NSAID, ACECLO and INDO show an advantageous activity profile. They fully blocked PGE2 production, inhibited IL-6 synthesis, and increased aggrecan synthesis. These effects appear advantageous for the longterm treatment of chronic joint diseases such as osteoarthritis.