Specific drug therapy of experimental osteoarthritis

Inhibition of estradiol-induced early osteoarthritic changes by tamoxifen

Previous studies on osteoarthritic changes induced by intraarticular injections of estradiol benzoate (EB) suggest estrogen as a risk factor in the development of knee osteoarthritis (OA). The present study observed the anti-arthritic effects of tamoxifen (TMX). Oophorectomized rabbits were subjected to intraarticular injections of vehicle control, EB, TMX, or EB/TMX for 3 weeks. The cartilage changes were assessed by light and scanning electron microscopic examination, enzyme histochemical analysis, and the amount of alcian blue stain binding to glycosaminoglycans. EB injections resulted in cell necrosis, chondrocyte clonings, and pittings, whereas the vehicle control, TMX, and EB/TMX-injected groups showed no histologic abnormalities. Histochemical analysis showed that the numbers of lactate dehydrogenase (LDH)-reactive chondrocytes in the EB-injected group were significantly reduced when compared to other groups (p less than 0.001). The injections of EB/TMX significantly reduced the chondrocyte numbers in the lateral superficial layer (p less than 0.05), compared with the vehicle injection. TMX-injected group revealed slight although insignificant decreases in chondrocyte numbers. The amount of alcian blue stains, representing the relative amount of proteoglycans, significantly decreased only in the superficial layer of the EB- and EB/TMX-injected groups (p less than 0.05). TMX, when concurrently injected with EB, antagonized the chondrodestructive effects of estradiol at the early stage of knee OA in rabbits. The results suggest the potential therapeutic use of TMX at the early stage of OA.

Hereditary joint disorder in progressive ankylosis (ank/ank) mice. II. Effect of high-dose hydrocortisone treatment on inflammation and intraarticular calcium hydroxyapatite deposits

Mice homozygous for the progressive ankylosis trait develop an inflammatory joint disorder associated with the intraarticular deposition of calcium hydroxyapatite. When affected (ank/ank) mice were treated with high doses of hydrocortisone, synovitis receded, development of cartilaginous and bony osteophytes halted, and calcium hydroxyapatite accumulated in and distended the synovial spaces. No changes, however, occurred in the joint morphology of hydrocortisone-treated normal (ank/+) mice. Since inhibition of inflammation by hydrocortisone treatment did not block apatite accumulation, intraarticular deposition of hydroxyapatite occurs independent of inflammation in progressive ankylosis.

Sustained-release indomethacin in the comprehensive management of osteoarthritis

Osteoarthritis, although primarily a degenerative joint disease, may be associated with significant secondary inflammation. Hydrolytic enzymes result in primary cartilage degradation; secondary inflammation occurs in response to degenerative cartilage breakdown products and crystal deposition. Humoral and cell-mediated immune responses have been described. Analgesic and anti-inflammatory agents play a major role in symptomatic relief. Anti-inflammatory activity of the nonsteroidal anti-inflammatory drugs has been ascribed to prostaglandin synthesis inhibition; recent studies suggest additional effects based on inhibition of neutrophil aggregation, superoxide radical generation, and lysosomal enzyme release. Indomethacin, the first of the newer nonsteroidal anti-inflammatory drugs, has a long history of use and patient acceptance. Sustained-release indomethacin (Indocin SR), a 75 mg formulation equivalent to three consecutive doses of conventional indomethacin, adds ease of administration and potential for improved compliance. Nonsteroidal anti-inflammatory drugs, used in conjunction with other therapeutic approaches, provide the opportunity for response that can be gratifying for both patients and physicians.