Effects of recombinant human interleukin‐1β on rabbit articular chondrocytes

Abstract

Using an in vitro model, we characterized the production of prostaglandin E,, 6-keto-prostaglandin F,, , and thromboxane B, by normal rabbit articular chondrocytes stimulated by interleukin-lp. The prostanoids were produced in a dose-and time-dependent manner, which was sensitive to actinomycin D and cycloheximide. Interleukin-1 also had a pronounced, but reversible, cytostatic effect on chondrocytes, which was not attributable to prostanoid or polyamine synthesis.Interleukin-1 (IL-l), a soluble mediator first found to be released by monocytes and macrophages, plays a critical role in immune regulation (1-3). IL-1 is also well established as a mediator of inflammation and has been identified in synovial fluids of patients with inflammatory diseases (43). There is an emerging body of evidence suggesting that IL-1 may therefore play a role in the etiology of the rheumatoid process in joints.The pathophysiologic manifestation of rheumatoid arthritis (RA) is characterized both as a proliferative disease of the synovial tissue and as the degradation of cartilage and bone at the inflamed joint (6). The potential relationship between IL-I and RA is further supported by the observation that synovial fibroblasts are induced to proliferate by IL-1 (7). Collagen (8), glycosaminoglycan (9), and prostaglandin E, (PGE,) (10) syntheses are enhanced, and the secretion of collagenase (1 1) and plasminogen activator is triggered (11,12) by IL-1. Similarly, IL-1 modulates cartilage and bone cells by the enhanced production of PGE, (13,14) and the release of proteinases (6). The elevation of these catabolic enzymes probably results ultimately in the breakdown of bone (15,16) and cartilage (17,18).In our effort to better define the response of articular chondrocytes to IL-1 in an in vitro model, we investigated two aspects of chondrocyte response to IL-1. First, the relative amounts of the cyclooxygenase products released, PGE,, 6-keto-prostaglandin F,, (6-keto-PGF, J , and thromboxane B, (TXB,), were studied. The effects of protein and RNA inhibitors on prostanoid release were also examined. Although the release of PGE, by chondrocytes in response to stirnulated mononuclear cell products or recombinant IL-I has been reported, the synthesis of other prostanoids has not been clearly defined. Second, we demonstrated the ability of IL-1 to influence the rate of chondrocyte growth in a reversible negative manner that is independent of prostanoid or polyamine synthesis. MATERIALS AND METHODSMaterials. Radioimmunoassay (RIA) kits for PGE,, 6-keto-PGF,,, TXB,, (methyL3H)thymidine, 3H-leucine, and Biofluor were purchased from New England Nuclear (Boston, MA). The cross-reactivities among the 3 prostanoids examined, using the RIA kits, were 51.4% at the 50%-bound point, as determined by the manufacturer. Tissue culture plastics were from Costar (Cambridge, MA). Dulbecco's modified Eagle's medium (DMEM) was pre-

Effects of human recombinant interleukin-1β on canine articular chondrocytes in three-dimensional culture

“…Chondrocyte culture-Canine chondrocytes were harvested, cultured and subcultured in monolayer, and cultured in 3-D medium, as described. 23,24 Briefly, full-thickness slices of grossly normal articular cartilage were aseptically obtained from the humeral head of 7 adult canine cadavers immediately after euthanasia. All aspects of the experimental protocol were performed simultaneously in samples from all dogs.…”

“…4,6,11,12,15,18,20 Interleukin-1 is generally added to the media of monolayer chondro-cyte or explant cultures of articular cartilage. 12,20,23,24 Cook et al [25][26] have described a 3-dimensional (3-D) culture technique that has advantages over monolayer and explant techniques with respect to cell morphology, differentiation, and matrix production and provides a more comprehensive model of articular cartilage and synovial fluid components of osteoarthritic joints. The purpose of the study reported here was to evaluate the effects of human recombinant IL-1β on canine chondrocytes cultured in a 3-D gel medium.…”

An aggrecan-degrading activity associated with chondrocyte membranes

“…Chondrocytes were prepared from bovine nasal septum cartilage obtained within 24 h of slaughtering and stored at 4 mC. Chondrocytes were isolated from the cartilage by sequential enzymic digestion with 1 mg\ml hyaluronidase, 0.25 % (w\v) trypsin and 3 mg\ml collagenase as described previously [13]. The cells were grown in monolayer culture in DMEM containing 25 mM Hepes and supplemented with 10 % fetal calf serum, 2 mM glutamine, 20 i.u.\ml nystatin, 100 i.u.\ml penicillin, 50 µg\ml gentamicin and 100 µg\ml streptomycin.…”

Chondrotoxicity of quinolones in vivo and in vitro

“…After 4 days of cultivation in supplemented DMEM medium at 37 ~ relative humidity/5.0 vol.-% CO2 in an incubator (standard conditions) fragments were disintegrated by enzymatic digestion with hyaluronidase, trypsin, and collagenase following the procedure of Chin and Lin (1988). Isolated chondrocytes were seeded into "Primaria plates", transferred to agar-coated cell culture flasks after 24 h, and further cultivated in tridimensional suspension culture (Basleer et al 1990).…”