Benoxaprofen stimulates proteoglycan synthesis in normal canine knee cartilage in vitro

Medical treatment of osteoarthritis in the horse - a review

The medical treatment of osteoarthritis (OA) in the horse is one of the most utilized therapeutic regimens in the equine practice. It is important to understand the anatomy of synovial joints and the pathophysiology of the disease process to treat OA adequately. Once a thorough understanding of the disease process is comprehended the proper combination of systemic nonsteroidal anti-inflammatory drugs (NSAIDs), intraarticular steroids, viscosupplementation and chondroprotectants can be used to treat the disease and inhibit further progression of degenerative changes to the cartilage surface. The equine practitioner is faced with many choices for controlling inflammation in OA. This review presents the background and appropriate uses of various NSAIDs such as phenylbutazone, flunixin meglumine, ketoprofen, naproxen, and carprofen as well as their associated toxicities. Various steroid formulations exist for intraarticular (IA) administration and much has been learned in the past decade regarding correct dosage, frequency of administrations, indications and toxicity. This review presents IA steroids and their indications in addition to various chondroprotective drugs that also exist to control inflammation and provide viscosupplementation. Data are also given on disease modifying OA drugs such as glucosamine and chondroitin sulphate that have more recently become available to the equine practitioner.

Pharmacological influence of antirheumatic drugs on proteoglycans from interleukin-1 treated articular cartilage

The purpose of this study was to examine whether drugs used in the treatment of arthritic disorders possess any inhibitory potential on the proteoglycanolytic activities of matrix metalloproteinases (MMPs), and to determine whether drugs which inhibit these enzymes also modulate the biosynthesis and release of proteoglycans (PGs) from interleukin-1-(IL-1) treated articular cartilage explants. The cartilage-bone marrow extract and the glycosaminoglycan-peptide complex (DAK-16) dose-dependently inhibited MMP proteoglycanases in vitro when tested at concentrations ranging from 0.5 to 55 mg/mL, displaying an IC50 value of 31.78 mg/mL and 10.64 mg/mL (1.9 x 10[-4] M) respectively. (R,S)-N-[2-[2-(hydroxyamino)-2-oxoethyl]-4-methyl-1-oxopentyl++ +]-L-leucyl-L-phenylalaninamide (U-24522) proved to be a potent inhibitor of MMP proteoglycanases (IC50 value 1.8 x 10[-9] M). None of the other tested drugs, such as possible chondroprotective drugs, nonsteroidal anti-inflammatory drugs (NSAIDs), disease modifying antirheumatic drugs (DMARDs), glucocorticoids and angiotensin-converting enzyme inhibitors tested at a concentration of 10(-4) M displayed any significant inhibition. Only U-24522, tested at a concentration ranging from 10(-4) to 10(-6) M, significantly inhibited the IL-1-induced augmentation of PG loss from cartilage explants into the nutrient media, whereas DAK-16 and the cartilage-bone marrow extract were ineffective. DAK-16 and the cartilage-bone marrow extract did not modulate the IL-1-mediated reduced biosynthesis and aggregability of PGs by the cartilage explants. The addition of 10(-5) M U-24522, however, partially maintained the aggregability of PGs ex vivo. In our experiments, both possible chondroprotective drugs as well as U-24522 demonstrated no cytotoxic effects on chondrocytes.

Basic fibroblast growth factor-induced glycosaminoglycan production in cultured vascular endothelial cells results from enhanced protein synthesis mediated by the lipoxygenase pathway

To investigate the intracellular regulation of glycosaminoglycan (GAG) production induced by basic fibroblast growth factor (bFGF), bovine aortic endothelial cells were cultured with recombinant human bFGF in the presence of [3H]glucosamine or [35S]sulfate. It was shown that bFGF-induced incorporation of the radioactive precursors into GAGs was diminished by lipoxygenase inhibitors, nordihydroguaiaretic acid (NDGA) and esculetin, but not by a cyclooxygenase inhibitor indomethacin. A protein synthesis inhibitor cycloheximide also diminished the enhancement of the [3H]glucosamine incorporation by bFGF. On the other hand, the incorporation of [14C]leucine into the acid-insoluble fraction was strongly inhibited by NDGA but not by indomethacin in the presence or absence of bFGF. It was also shown that bFGF significantly increased the incorporation of [14C]xylose into GAGs. The present data suggested that bFGF may increase the number of GAG chains as a result of enhanced protein synthesis including xylosyl transferase through the lipoxygenase pathway of arachidonic acid metabolism in vascular endothelial cell layer.

Effects of tiaprofenic acid on the concentration and metabolism of proteoglycans in normal and degenerating canine articular cartilage

The effects of tiaprofenic acid (TPA), a nonsteroidal antiinflammatory drug with high potency as a cyclooxygenase inhibitor, on the metabolism of normal and degenerating articular cartilage were examined. When present in the culture medium in clinically relevant concentrations encompassing those achieved in synovial fluid of patients treated with the drug, TPA had no significant effects on net proteoglycan synthesis in organ cultures of normal, osteoarthritic or atrophic canine articular cartilage. When fed to dogs for 8 weeks in a daily dose of 100 mg, TPA had no apparent effect on cartilage water content or uronic acid concentration. The suppression of net cartilage proteoglycan synthesis caused by immobilization was not affected by administration of TPA nor did the drug affect the proportion of newly synthesized glycosaminoglycans recovered from the spent culture medium, suggesting that it did not increase proteoglycan catabolism or affect the integrity of the cartilage matrix.

Effects of nonsteroidal anti-inflammatory drugs on chondrocyte metabolism in vitro and in vivo

Salicylates and several other nonsteroidal anti-inflammatory drugs (NSAIDs) that are commonly employed in the treatment of osteoarthritis effectively decrease joint pain and increase mobility. Results from in vitro studies indicate that, in addition, some of these compounds affect proteoglycan metabolism of articular cartilage. Data from in vivo studies suggest that salicylate administration may accelerate articular cartilage damage in several animal models of osteoarthritis. At in vitro concentrations comparable to those that are achieved in the synovial fluid of patients treated with the drug, several NSAIDs suppress proteoglycan synthesis by the chondrocyte. Salicylate has been shown to inhibit the enzymes involved in the early stages of chondroitin sulfate biosynthesis. These NSAID-related effects on chondrocyte metabolism appear unrelated to inhibition of prostaglandin synthetase, and are much more profound in osteoarthritic cartilage than in normal cartilage, due to enhanced uptake of NSAIDs by the osteoarthritic cartilage. Depletion of matrix proteoglycans appears to be a major factor in the increased vulnerability of chondrocytes in degenerating cartilage to effects of NSAIDs. Some NSAIDs may be bound to matrix components. If similar changes occur in the cartilage of patients with arthritis treated with NSAIDs, despite the symptomatic improvement that these drugs produce, cartilage degeneration could be accelerated.

Articular cartilage response to arthroscopic surgery: a review of current knowledge

This review is intended to point out the many variables affecting articular cartilage around the time of arthroscopic surgery. Despite the rapid clinical recovery of arthroscopic surgery patients, there may be considerable articular cartilage inhibition related to preoperative, intraoperative, and postoperative factors. Risks to the patient and his joint can be minimized by careful management of these known variables.

Effect of indomethacin and benoxaprofen on immune complex interaction with cultured glomerular cells

Prostaglandins of the E series (PGE) increased immune complex (IC) interaction with cultured glomerular cells in a previous study. The present study examines the effect of indomethacin (IND) and benoxaprofen (BEN) on interaction of IC with cultured cells and their effect on PGE enhanced cell-IC interaction. IC were formed with antigen modified to produce a cationic (CAT) charge or left unmodified (UM). IND increased cell interaction with IC formed with CAT antigen (CAT IC). BEN had no effect on the interaction of IC formed with either antigen. The combined use of IND and PGE increased CAT IC interaction to the same degree as when each was used alone. BEN prevented the increased CAT IC interaction produced by IND or PGE when used in combination. Protamine sulfate prevented the enhanced CAT IC interaction produced by IND or PGE while sodium heparin had no effect. The results indicate IND and PGE increase cell IC interaction, the increase is not additive when they are combined, the effects of both are blocked by BEN, and protamine sulfate inhibits the effects of both compounds.