Triamcinolone hexacetonide protects against fibrillation and osteophyte formation following chemically induced articular cartilage damage

Effect of betamethasone and exercise on equine carpal joints with osteochondral fragments

Osteochondral fragments were created arthroscopically on the distal aspect of both radial carpal bones in 12 horses. On day 14 after surgery, one middle carpal joint of each horse was injected with 2.5 mL Betavet Soluspan (3.9 mg betamethasone sodium phosphate and 12 mg betamethasone acetate per milliliter) and the contralateral joint was injected with 2.5 mL saline as a control. Intra-articular treatments were repeated on day 35. On day 17, six horses began exercising 5 days per week on a high-speed treadmill. The other six horses were kept in box stalls throughout the study as nonexercised controls. On day 56, all horses were examined clinically and radiographically and then were euthanatized. Samples were obtained for histological, histochemical, and biochemical evaluation. Mild lameness was observed in five of the six exercised horses at day 56; four horses were lame in the control limb and one horse was lame in the treated limb. Of the five nonexercised horses evaluated for lameness, two were lame in the control limb, two were lame in the treated limb, and one was lame in both the control and the treated limb. No differences were noted on radiographs or palpation of steroid treated limbs versus control limbs. Firm reattachment of the osteochondral fragment to the radial carpal bone occurred in all but three joints. Gross cartilage damage was not different between steroid-treated joints and joints injected with saline. Histologically, there were no significant detrimental effects of beta-methasone with or without exercise, but there was a tendency for more pathological change in treated joints. No significant difference in the water content or uronic acid concentration was detected between treated and control joints. Intra-articular betamethasone administration in this carpal chip model was not associated with any significant detrimental effects in either rested or exercised horses.

Intraarticular injections with methylprednisolone acetate reduce osteoarthritic lesions in parallel with chondrocyte stromelysin synthesis in experimental osteoarthritis

OBJECTIVE

To examine the effect of intraarticular injections of methylprednisolone acetate (MA) on osteoarthritic lesions and chondrocyte stromelysin synthesis in experimental osteoarthritis (OA).

METHODS

In 15 mongrel dogs, the anterior cruciate ligament of the right knee was sectioned by a stab wound. Eight dogs received intraarticular injections of MA (20 mg) at the time of surgery and 4 weeks later; 7 had no treatment. The dogs were killed 8 weeks after surgery. Five normal dogs were used as controls. Macroscopic evaluation of the lesions, including measurements of osteophytes and areas of surface lesions on the condyles and plateaus, was conducted, along with histologic evaluation of the severity of lesions. Immunohistochemical analysis was carried out using a rabbit polyclonal antibody against stromelysin, followed by evaluation of matrix and chondrocyte staining using morphometric analysis.

RESULTS

Treatment with MA significantly reduced the incidence (P < 0.0004) and size (P < 0.0001) of osteophytes. The histologic grading of cartilage lesions was also significantly reduced both on condyles (P < 0.01) and on plateaus (P < 0.002). Immunohistochemical studies revealed, for OA cartilage, a marked increase (P < 0.002) in the percentage of chondrocytes positive for stromelysin and in the intensity of staining throughout all the layers of the cartilage, as well as specific matrix staining (P < 0.005). Treatment with MA reduced staining at both the chondrocyte (P < 0.002) and the matrix (P < 0.01) levels toward normal.

CONCLUSION

These findings provide additional evidence for the protective effect of corticosteroid injections on OA lesions, and indicate that the effect of this drug may be mediated through the suppression of stromelysin synthesis.

In vivo effects of naproxen on composition, proteoglycan metabolism, and matrix metalloproteinase activities in canine articular cartilage

Naproxen is a nonsteroidal anti-inflammatory drug commonly used in the clinical treatment of joint disease. In this study, its effect in vivo on the biochemical composition, metabolic activities, and metalloproteinase activities of normal canine articular cartilage was analyzed. The articular cartilage from the knee joints of dogs who had been given naproxen for 4 weeks to maintain a serum level of 40-50 micrograms/ml was examined. Control animals were given a placebo. Treatment with naproxen was not found to change the composition (water, collagen, and proteoglycan) of the articular cartilage. The culture studies of cartilage explants indicated that proteoglycan synthesis rates were unaffected by the treatment with naproxen but that proteoglycan release from the tissue was suppressed. Analysis of the cartilage for matrix metalloproteinase activities showed reduced activity of neutral matrix metalloproteinase by 80%, of collagenase by 40%, and of gelatinase by 87%, with no change in activity of acid metalloproteinase or of tissue inhibitor for metalloproteinase. These findings indicate that in vivo treatment with naproxen has the capacity to modulate catabolic activities in articular cartilage.

In vitro effects of NSAIDs and corticosteroids on the synthesis and secretion of interleukin 1 by human osteoarthritic synovial membranes

The mechanism(s) of action of NSAIDs and corticosteroids in arthritic diseases has been the subject of intensive investigation in recent years. Although NSAIDs and corticosteroids have many effects, their possible ability to modify the disease course in patients has not been fully documented. In an attempt to characterize the mechanism(s) involved in the effect of some NSAIDs in joint diseases, we investigated the effect of three concentrations within the pharmacological (260 micrograms/ml) and therapeutic (26 and 2.6 micrograms/ml) ranges of tiaprofenic acid in the synthesis and release of interleukin (IL-1) alpha and beta in human OA synovial membranes. The effect of tiaprofenic acid was compared to the effect of two other NSAIDs, sodium salicylate (160 micrograms/ml) and indomethacin (1.5 micrograms/ml), and to a corticosteroid, hydrocortisone (0.725 and 7.25 micrograms/ml). This study was carried out using human OA synovium explants incubated in the presence or absence of LPS. In the absence of LPS and at therapeutic concentration, tiaprofenic acid decreased both the synthesis and release of IL-1 beta. A less marked effect of the drug was noted under LPS treatment, and inhibition of the production/secretion of IL-1 beta was found only at pharmacological concentration. Sodium salicylate and indomethacin did not share this action, and demonstrated either no effect or enhancement of IL-1 beta synthesis, respectively, in the presence of LPS. As expected, hydrocortisone demonstrated a marked decrease on IL-1 alpha and IL-1 beta, both in the presence and absence of LPS. These results bring forth new information on the action of these drugs and their effects on the OA pathophysiological process.

Intra-articular corticosteroid reduces joint stiffness after an experimental periarticular fracture

Early care after surgery or trauma to the extremities often includes a period of immobilization. The resultant joint stiffness may require extensive rehabilitation and may permanently limit function of the limb. Posttraumatic joint stiffness is particularly vexing in the small joints. In an experimental model, we tested the effects of intra-articular corticosteroid injections on stiffness in a joint at risk of posttraumatic joint stiffness. Triamcinolone was injected into ankle joints of rabbits after distal tibial fractures. Three weeks after injury, joint stiffness increased 34% in ankles injected with the steroid. Stiffness in ankles injected with saline solution and in ankles treated with no injection increased 133% and 224%, respectively. Limb swelling and tibial torsional strength to failure were not significantly affected by either of the treatments.

Passive role of articular chondrocytes in the pathogenesis of acute meniscectomy-induced cartilage degeneration

The importance of viable articular chondrocytes and enzymes or factors from surgically traumatized synovium in the pathogenesis of acute meniscectomy-induced cartilage degeneration was examined in guinea pigs (nine groups of five animals each). Iodoacetate injected intra-articularly was used to kill articular chondrocytes of guinea pigs prior to meniscectomy to determine if they were active participants in the acute lesion induction. Lesions of similar severity to those occurring in animals with viable chondrocytes at the time of surgery were observed, suggesting that the chondrocytes were not actively involved in the pathogenesis in this group. In an additional group of guinea pigs in which chondrocytes were killed by iodoacetate, the medial collateral ligament was transected to determine if acute degenerative changes could be induced in acellular cartilage exposed to a surgical manipulation that does not by itself induce lesions but does expose cartilage to enzymes/factors from traumatized synovium. Transecting the medial collateral ligament and entering the joint space without induction of instability via meniscectomy did not result in histologic evidence of cartilage damage. This suggests that synovial trauma and mild inflammation were insufficient to induce matrix degeneration in the absence of abnormal load bearing. In further support of this, guinea pigs subjected to unilateral sciatic neurectomy at the time of meniscectomy were protected against development of acute cartilage degeneration. Results of this study suggest that articular cartilage devoid of viable chondrocytes at the time of meniscectomy responds acutely in much the same way as intact cartilage subjected to this procedure.

Protective effect of rimexolone on cartilage damage in arthritic mice: a comparative study with triamcinolone hexacetonide

We studied the effect of the local steroid preparation rimexolone on cartilage metabolism in arthritis and normal joints. Prolonged anti-inflammatory action was evident after intraarticular injection of a single dose of 450 micrograms into mice with monoarticular antigen-induced arthritis. Suppression of inflammation lasted for at least 21 days. A single dose of 25 micrograms of the anti-inflammatory steroid triamcinolone hexacetonide (THA) induced comparable suppression in the initial stage of the arthritis, but the suppressive action was of shorter duration. Both drugs significantly prevented osteophyte formation, which is a characteristic feature of this type of experimental arthritis. Although chondrocyte proteoglycan (PG) synthesis in patellar cartilage was significantly suppressed upon injection in normal joints, both steroids counteracted the severe suppression of PG synthesis in arthritic joints. These data indicate that although steroids may have significant side effects on chondrocytes, the overall effect on arthritic chondrocytes is beneficial. An advantage of rimexolone over THA is its prolonged retention, which may explain its sustained anti-inflammatory action, and the lack of systemic effects.

Spontaneous osteo-arthritis of the knee-joint in C57BL mice receiving chronic oral treatment with NSAID's or prednisone

In a statistically planned study based on quantitative radiography, treatment for 25-26 weeks with the 2 NSAIDs, diclofenac sodium, or indomethacin (both 0.5 and 1.5 mg/kg p.o. daily), or prednisone (6 mg/kg p.o.) had no influence on the progression of spontaneous osteo-arthritis of the knee-joint of the C57BL mouse, by comparison with placebo-treated controls.

Protective effects of corticosteroids on cartilage lesions and osteophyte formation in the Pond-Nuki dog model of osteoarthritis

The in vivo effects of corticosteroids on osteoarthritic (OA) lesions were examined in 12 dogs in which the anterior cruciate ligament had been sectioned. Six were treated with oral prednisone and 6 were treated with intraarticular (IA) injections of triamcinolone hexacetonide (TH), at surgery and 4 weeks later. Twelve other operated dogs received no treatment. All dogs were killed 8 weeks postsurgery. Four of 15 normal control dogs received IA TH injections. Operated untreated dogs developed significant cartilage lesions on the femoral condyles and tibial plateaus with prominent osteophytes. Operated dogs treated orally or with IA injections had a significant reduction in osteophyte size. Cartilage erosions on femoral condyles were observed in 25% of the untreated dogs, 8% of the dogs receiving oral prednisone, and none of the dogs receiving IA TH. In both groups of treated dogs, the size of the tibial plateau lesions was significantly reduced compared with the operated untreated dogs. Histologically, corticosteroids significantly reduced the severity of OA structural changes of the cartilage on both medial and lateral femoral condyles and tibial plateaus in operated animals, with the exception of the lateral plateaus of those treated orally. In electron microscopy studies, we found no evidence of increased cell degeneration or death associated with steroids. IA corticosteroids had no deleterious effects on normal articular cartilage. These results indicate that glucocorticoids administered orally or intraarticularly are effective against the development of OA lesions in this model.

Anti-rheumatic drugs and cartilage

In this chapter an attempt has been made to draw together the known biology of cartilage and some of the mechanisms thought to be responsible for its failure in arthritis. The picture is far from complete but we are now in a good position to use this information to help appraise the pros and cons of the wide range of drugs now available to treat articular disorders. For convenience, these drugs were classified as NSAIDs, corticosteroids and chondroprotective agents. The influence of each of these classes on the metabolism of cartilage was examined in the light of published laboratory and clinical studies. It has been clearly shown that not all NSAIDs are the same. While many of the older drugs provided no benefit to cartilage metabolism, and in some instances suppressed it, the more recently discovered molecules appear to be free of these undesirable effects. Tiaprofenic acid, diclofenac and piroxicam emerged as drugs with little or no harmful effects on cartilage metabolism when used at concentrations within the human therapeutic range. For all NSAIDs, their potential effects on cartilage must be weighed against their respective anti-inflammatory potency, half-life, and effects on the gastric mucosa and other tissues. Other chapters in this book have addressed these important problems. The long-acting corticosteroids, betamethasone and triamcinolone hexacetonide, also appear to offer some benefit in the management of OA; however, as in RA, their use should be restricted to short-term applications. In terms of cartilage metabolism the chondroprotective agents pentosan polysulphate, Arteparon and Rumalon have been the most extensively studied class of drugs. While the laboratory studies have provided convincing evidence of their chondroprotective efficacy, it has been difficult to prove this clinically. This dichotomy of opinion (laboratory versus clinical) stems largely from the inadequacy of the methodologies currently available for the objective clinical assessment of patient response to anti-rheumatic drug therapy. With the advent of nuclear magnetic resonance imaging techniques and monoclonal antibodies to detect specific proteoglycan breakdown fragments in synovial fluid and plasma, the prospects for a unified research approach for the evaluation of these agents may now be possible.

Spontaneous cartilage degeneration in guinea pigs

Spontaneous degeneration of the knee joint cartilage in male Hartley guinea pigs was studied by light microscopy in animals aged 3-18 months. Unilateral focal degeneration, characterized by chondrocyte death and proteoglycan loss with surface fibrillation, was observed on the medial tibial plateau in 2 of 5 guinea pigs that were 3 months old. The incidence and severity of the lesions increased with age, and by 12-18 months of age, all animals had moderate-to-severe degeneration of the medial tibial plateau, femoral condyle, and meniscus. Lesions were not present on the lateral aspect of the knee joint in any of the animals.

Crystals, inflammation, and osteoarthritis

Calcium pyrophosphate and apatite crystals are common in osteoarthritic knee effusions. One or the other crystal was found in 60 percent or more of cases. These crystals offer the potential for mechanical effects in cartilage but are also often phagocytized by synovial cells. A low-grade inflammation with release of proteases and other mediators of inflammation may be an important factor in the pain and joint damage of osteoarthritis. Crystal-associated changes may merit specific attention in any future approach to therapy.

Studies of pharmacokinetics and therapeutic effects of glucocorticoids entrapped in liposomes after intraarticular application in healthy rabbits and in rabbits with antigen-induced arthritis

Dexamethasone palmitate (DMP) entrapped in liposomes of defined sizes was administered intraarticularly in healthy rabbits and in rabbits with antigen-induced arthritis. The pharmacokinetics and therapeutic effect of liposomal DMP were measured and compared with corresponding experiments using microcrystalline triamcinolone acetonide (TAC). The small DMP liposomes (diameter 160 nm) showed a greater decrease in joint circumference than the 3-times-higher dose of microcrystalline TAC. Moreover, about 98% of administered TAC had already disappeared from the joint 6 h after injection, whereas about 36% of liposomal DMP was still measured in synovial fluid and synovium at the same time. Increasing the vesicle diameter from 160 to 750 nm (large liposomes) improved the retention of DMP by a factor of 2.6 within 48 h after injection in healthy rabbits. In addition, none of the liposomal glucocorticoid preparations ever suppressed the endogenous plasma cortisol level, which is in contrast to the suppression measured after administration of the microcrystalline preparation.