Interleukin-1 stimulation of equine articular cells

Abstract

Prostaglandin E 2 ( pge 2) and stromelysin are produced by equine chondrocytes and synovial cells in vitro in response to recombinant human (rh) interleukin-1 (IL-1) α and β, and equine mononuclear cell supernatants ( mcs) containing IL-1. However, culture conditions are important. pge 2 concentrations increase in proportion to the concentration of fetal calf serum ( fcs) in the culture medium, whereas stromelysin concentrations are inversely proportional to the concentration of fcs. Equine mcs, containing a lower concentration of IL-1 than the concentration of rhIL-1 used in these experiments, stimulated production of much higher levels of pge 2 than rhIL-1. In addition, equine mcs induced the production of broadly similar levels of pge 2 by both chondrocytes and synovial cells, whereas rhIL-1 was more active on equine synovial cells than equine chondrocytes. Although equine Mcs induced both stromelysin and PGEZ production by equine articular cells, on the whole rhIL-1 failed to induce stromelysin production. This supports previous observations of species restrictions in the activity of human IL-1 on equine cells. Therefore, experiments using mammalian cells and heterologous IL-1 should be interpreted with caution.