Effects of the hydroxamic acid derivate Ro 31-4724 on the metabolism and morphology of interleukin-1-treated cartilage explants.

Matrix metalloproteinases (MMPs) belong to the key enzymes of the proteolytic destruction of cartilage matrix during chronic rheumatic diseases. Our work focused on the inhibitory potential of the hydroxamate Ro 31-4724 on the activity of MMP-proteoglycanases as well as on the viability, morphology and proteoglycan metabolism of interleukin-1 (IL-1)-treated bovine articular cartilage explants. The in vitro activity of MMP-proteoglycanases as well as the release of proteoglycans from IL-1-treated cartilage explants were significantly and concentration-dependently inhibited by Ro 31-4724 tested at concentrations ranging from 1 nmol/l to 10 mumol/l.

The proteoglycan metabolism, morphology and viability of articular cartilage treated with a synthetic matrix metalloproteinase inhibitor.

Matrix metalloproteinases (MMP) are among the key enzymes responsible for the proteolytic destruction of articular cartilage during chronic rheumatic diseases. Articular cartilage is one potential target for drugs designed to inhibit the activity of MMPs in order to stop or to slow down the proteolytic destruction of the extracellular matrix of cartilage. The purpose of this study was to investigate the effect of the synthetic inhibitor of MMPs U-24522 for its ability (1) to inhibit in vitro the activity of MMP-proteoglycanases; (2) to modulate the morphology and viability of cartilage explants; and (3) to modify the biosynthesis and release of proteoglycans from articular cartilage explants.

The inhibitory effects of antirheumatic drugs on the activity of human leukocyte elastase and cathepsin G.

The serine proteinases elastase and cathepsin G from polymorphonuclear granulocytes play a critical role in articular cartilage degradation, not only as proteolytic enzymes able to degrade the extracellular matrix but also by additionally modulating the level of active matrix metalloproteinases, key enzymes of the proteolytic destruction of cartilage during rheumatoid arthritis. The aim of our study was to examine whether anti-inflammatory drugs and selected compounds inhibited elastase and cathepsin G, and also to determine whether it is necessary to use a highly purified elastase preparation to screen drugs for their ability to block the activity of this enzyme. Eglin C and the glycosaminoglycan-peptide complex DAK-16, at concentrations ranging from 10(-9) to 10(-4) M, dose-dependently inhibited elastase and cathepsin G while the nonsteroidal anti-inflammatory drugs oxyphenbutazone, phenylbutazone, sulfinpyrazone and diclofenac-Na required high concentrations to demonstrate some inhibitory effects on the activity of both enzymes.

Influence of chloroquine and other substances on the collagenolytic activity in human osteoarthritic cartilage in vitro.

To investigate the influence of certain drugs and agents upon collagenolytic activity in human cartilage, homogenized articular cartilage from osteoarthritic human hips was incubated with dexamethasone, diclofenac, indometacin, phenazone, phenylbutazone, tiaprofenic acid, sulfasalazine, penicillamine, chloroquine, cysteine and a glycosaminoglycan-peptide complex (DAK-16). Collagenolytic activity was quantitated by the release of soluble hydroxyproline-containing peptides. The presence of collagenase in osteoarthritic cartilage was proved by the typical 75:25 cleavage products of type I collagen.

Histomorphological studies on the effect of recombinant human superoxide dismutase in biochemically induced osteoarthritis.

Enzymatic scavenging of .O-2 radicals by injections of superoxide dismutase has been described to inhibit the free radical reactions resulting in tissue damage. Using a biochemically induced model of osteoarthritis (OA) in the knee joints of hens, we investigated the histomorphological alterations under therapy with recombinant human superoxide dismutase (rH-SOD) in various doses by histological-histochemical grading.

Prolonged effect of iodoacetate on articular cartilage and its modification by an anti-rheumatic drug.

The intra-articular injection of iodoacetate into the knee joint of rats produced changes in the articular cartilage which resembled those of osteoarthritis. It caused virtually total loss of many of the oxidative enzymes, indicating inhibition of the main oxidative pathways. Treatment with an anti-rheumatic drug had little early effect but ultimately led to partial restoration of these pathways.

Immunohistochemical localization of articular cartilage proteoglycan and link protein in situ using monoclonal antibodies and lectin-binding methods.

Lectins have specificity for certain carbohydrate structures in macromolecules. Lectins are, therefore, useful histochemical tools for demonstrating the composition and localization of components of connective tissue matrices, such as articular cartilage. In order to assess the significance of observed lectin-binding patterns, experiments were performed in which monoclonal antibodies against chondroitin sulphate- and keratan sulphate-containing proteoglycans and link proteins were applied to sections of bovine articular cartilage after enzymatic digestion with chondroitinase ABC and keratanase.

Structural and metabolic changes in articular cartilage induced by iodoacetate.

The chemically induced injury to articular cartilage, caused by two successive intra-articular injections of sodium iodoacetate, has been used in studies on the effects of anti-inflammatory and of potentially chondroprotective agents. It has been assumed that the injurious effects are caused by inhibition of the glycolytic pathway. In the present study this inhibition has been shown to be greater than expected from in vitro studies, and to influence equally other oxidative pathways.

Human recombinant interleukin-1 alpha and beta and articular tissue integrity. An in vivo study on hens and rats.

Human recombinant interleukin-1 alpha or beta was injected intraarticularly several times into the knee joints of rats and hens at different dosages (50-2000 ng) and intervals. No loss of cartilage detectable by width of the radiological joint space and no degenerative changes of subchondral bone could be observed during 16 weeks using X-ray analysis. The macroscopical examination of articular cartilage of hens after this period and of rats after one year showed no morphological cartilage damages.

Influence of some natural and semisynthetic agents on elastase and cathepsin G from polymorphonuclear granulocytes.

The in vitro effect of eglin C, glycosaminoglycan-peptide complex "DAK 16", glycosaminoglycan polysulfate and sodium pentosan polysulfate on the PMN-enzymes elastase and cathepsin G was investigated. The activity of elastase and cathepsin G was measured with the highly specific chromogenic substrates methoxysuccinyl-l-ala-l-ala-l-pro-l-val-p-nitroaniline and succinyl-l-ala-l-ala-l-pro-l-phenyl-alanin-p-nitroaniline. Eglin C and DAK 16 displayed a pronounced inhibition of PMN-elastase and PMN-cathepsin G.

[Pharmacologic studies on the antidegenerative effect of ademetionine in experimental arthritis in animals].

A standardized pharmacological model of biochemically induced osteoarthritis in the knee joint of laboratory animals was used for the study of a possible antidegenerative effect of ademetionine (S-adenosyl-methionine, active substance of Gumbaral) in-vivo. Four days after the initial induction of osteoarthritis by 2 intraarticular injections of 0.6 mg sodium iodoacetate into the left knee joint of adult hens, the therapy started with once-weekly intraarticular doses of 0.

Pharmacological influence on polymorphonuclear granulocytes elastase under various test conditions.

The effect of diclofenac-Na, glycosaminoglycanpolysulfate (GAGPS), eglin C and alpha 1-proteinase inhibitor on the activity of elastase from polymorphonuclear granulocytes (PMN-elastase) was tested under various conditions. The synthetic substrate methoxysuccinyl-1-ala-1-pro-1-val-p-nitroaniline was used to measure the activity of the enzyme. The inhibition or activation of PMN-elastase by the test substances was dependent on the type and concentration of buffer, the pH, the presence of a tenside and most notably, the presence of electrolytes.

Histomorphological and lectin-histochemical confirmation of the antidegenerative effect of diclofenac in experimental osteoarthrosis.

The integrity of cartilage matrix depends on the homeostasis of synthetic and degradative processes. Any disturbance of the rate of synthesis and catabolism may alter the amount of matrix components (e.g.

[The effect of anti-inflammatory agents on the granulocyte enzymes elastase and cathepsin G].

Effect of Nonsteroidal Anti-inflammatory Drugs on the Activity of Elastase and Cathepsin G from Human Polymorphonuclear Leukocytes. Several anti-inflammatory drugs display qualitative and quantitative different effects upon elastase and cathepsin G. Phenylbutazone, oxyphenbutazone, sulfinpyrazone and diclofenac-sodium proved to be the most efficient inhibitors of elastase and cathepsin G.

The influence of NSAIDs on morphology of articular cartilage.

A large number of experimental data have given evidence that many NSAIDs can inhibit the synthetic processes of connective tissue in-vitro and ex-vivo. During the past 18 years we have investigated the in-vivo effect of antirheumatic drugs on knee joint cartilage using rats and hens. Single or once-weekly intraarticular injections of salicylates, indomethacin, phenylbutazone, naproxen, ibuprofen, clofezone, fufenamic acid, niflumic acid, or dexamethasone induced morphological alterations in the joint cartilage and subchondral bone, which were demonstrable by means of histology, stereoelectron-microscopy, biochemistry and X-ray.

[Autoradiography studies of the effect of oxaceprol on the metabolism of joint cartilage in vitro and in vivo].

Using the radiolabelled precursors (3H-Glucosamine, 3H-proline) and a new procedure of quantitative microautoradiography we investigated the influence of N-acetyl-L-hydroxyproline (Oxaceprol) on anabolic processes in joint cartilage tissue of hens. After in vitro incubation, Oxaceprol stimulated the uptake of 3H-glucosamine and 3H-proline in chondrocytes and enhanced the incorporation of 3H-proline into the macromolecular structures of the cartilage matrix. Also, after in vivo intra-articular injection of Oxaceprol into the knee joints we could demonstrate a significant increase of intracellular glucosamine uptake.

Chemical model of osteoarthritis--a pharmacological evaluation.

For pharmacological testing of drugs with antidegenerative potency we developed an animal model of biochemically induced osteoarthritis (OA) by blocking the glycolytic energy metabolism and synthetic processes in articular chondrocytes. After local injection of sodium iodoacetate osteoarthritic reactions will progress within 2-4 months. Using a standardized radiological, histological, and macroscopical grading we could demonstrate that corticosteroids and some NSAID exert negative effects on articular cartilage, while a few other NSAID showed no influence.

[Orienting animal experiment studies on the effect of fenbufen on healthy and arthrosis-induced articular cartilage tissue in vivo].

Over a period of 3 months weekly intraarticular injections of fenbufen into the knee joint of hens did not induce any significant degenerative alterations of the articular cartilage. Experimental osteoarthrosis biochemically induced by iodoacetate in the knee joint of our laboratory animals was not enhanced by weekly intraarticular applications of fenbufen or its metabolite biphenyl-acetic acid. Joint space measurements as well as other radiological and macroscopical examinations of the knee joints confirmed that fenbufen and biphenyl-acetic acid had no negative influence on articular cartilage.

[Experimental gonarthrosis in rats and its therapy with glycosaminoglycan polysulfate (GAGPS)].

In good correlation to earlier results in hens we found that after intraarticular injections of iodo-acetate into the knee joint of rats, degenerative alterations of the articular cartilage and subchondral bone tissue develop within 2-4 months. The radiological, histological and macroscopical appearance of these degenerative processes in rats is quite similar to those in human osteoarthrosis (OA). Drug treatment of these rats with twice weekly subcutaneous doses of 1.

[Experimental confirmation of the antiarthritic activity of glycosaminoglycan polysulfate].

By the use of a biochemically induced animal model of osteoarthrosis we studied the chondroprotective properties and antiarthrotic potency of glycosaminoglycan-polysulfate (GAGPS: Arteparon) in-vivo. Under reproducible experimental conditions and using quantitative analytical methods (joint space measurements, radiological and macroscopic evaluations) we were able to demonstrate that intraarticular or intramuscular applications of GAGPS can significantly reduce the intensity and progression of joint degeneration. The therapeutic effect of GAGPS was dose-dependent, and noticeable not only in the early stages of experimental osteoarthrosis but also when therapy was begun in the more advanced phases of joint degeneration.

[Pharmacologic evaluation of the feasibility of cartilage therapy in degenerative joint diseases (arthroses)].

Due to their pharmacological properties most antiphlogistic/antirheumatic drugs are successfully used for treatment of inflammatory rheumatic diseases, but they are not able to counteract cartilage degeneration in osteoarthrosis. For specific therapy of osteoarthrosis only those drugs are suitable, which are able to inhibit enzymatic breakdown of articular cartilage, stimulate anabolic processes in cartilage, and to enhance the supply of nutritional and energy substrates for the cartilage cells. In this respect drugs such as Arteparon, Rumalon, Dona 200-S, Glyvenol or Pentosan polysulfate are of interest.

Histological investigations of the antiarthrotic effect of tribenoside (Glyvenol) in experimental osteoarthrosis.

Experiments in adult hens with chemically induced osteoarthrosis or osteoarthritis (OA) of the knee joint have shown that daily treatment with tribenoside (Glyvenol) in single oral doses of 50 mg/kg or 150 mg/kg markedly reduced the intensity and frequency of joint degeneration. We investigated the inhibitory effect of tribenoside on OA by histological techniques. Comparisons of articular cartilage from untreated and treated animals showed no qualitative differences in the alterations of the morphology and histopathology of the tribenoside treated specimens.

The inhibitory effects of steroidal and non-steroidal antirheumatic drugs on articular cartilage in osteoarthrosis and its counteraction by a biological GAG-peptide complex (Rumalon).

In-vitro studies have confirmed that various corticosteroids and also many nonsteroidal antirheumatic drugs exert inhibitory effects on anabolic processes in connective tissue cells. Depending on dose and at concentrations that in many cases correspond to therapeutic plasma levels, these drugs may lead to a pronounced reduction or complete blockade of synthesis of the proteoglycans and collagen of the cartilage matrix. Our in-vivo animal experiments have shown that single or repeated intraarticular applications of various antiinflammatory antirheumatics into the knee joint of hens or rats can induce progressive joint degeneration within 3-4 months.