Changes in bone mineral density in rat adjuvant arthritis

Bilateral Distal Femoral Flexion Deformity after Total Knee Arthroplasty in a Patient with Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune systemic disease with predominant peripheral polyarthritis, often leading to severe joint destruction. This is a case report of an 81-year-old woman with longstanding severe rheumatoid arthritis requiring multiple orthopaedic operations for joint destruction since 2000. These operated joints improved her functional mobility until recently, when she found that her knees were fixed at around 70° of flexion with limited motion. There was chronic progressive flexion deformity of bilateral distal femurs, which was an extremely rare complication of total knee arthroplasty.

The Effects of α-Viniferin on Adjuvant-Induced Arthritis in Rats

This study was performed to assess the efficacy of α-viniferin (Carex humilis Leyss) on adjuvant-induced arthritis in rats. Adjuvant arthritis was induced by a single subcutaneous injection of 0.1 ml complete Freund's adjuvant (CFA) containing 7.5 mg Mycobacterium butyricum suspended in 1 ml sterile paraffin oil into the right hind paw. Forty female Sprague-Dawley rats were injected. Righting reflex was uniformly lost and considered to be the initial point of arthritis development on day 7 after CFA injection. Rats were divided into four groups, and upon development of arthritis, tested groups were orally administered 3 or 10 mg/kg α-viniferin or 10 mg/kg ketoprofen every day for 14 days. The control group was orally administered 2 ml of physiological saline solution. Bone mineral density (BMD), radiological changes and edematous volumes were measured for 35 days. α-viniferin suppressed the development of inflammatory edema, and inhibited the bone destruction, noted with a decrease in BMD ( p <0.05). Hind paw edema volume, BMD and radiological changes did not differ significantly in the ketoprofen and α-viniferin groups during the entire study period. In conclusion, α-viniferin suppressed arthritic inflammation and bony change in rats.

Suppression of adjuvant arthritis by hesperidin in rats and its mechanisms

The citrus flavonoid hesperidin has been reported to possess a wide range of pharmacological properties. We have investigated the preventive and therapeutic effects of hesperidin on the development of adjuvant arthritis (AA), a rat model of rheumatoid arthritis (RA). Freund's complete adjuvant was used to induce AA in rats. Secondary paw swelling, polyarthritis index and histopathological assessment of ankle joints were used to evaluate the effects of hesperidin on AA rats. Concanavalin-A-induced T-lymphocyte proliferation and interleukin (IL)-2 production by splenocytes were measured using the MTT assay. Levels of IL-1, IL-6 and tumour necrosis factor (TNF)-α secreted by peritoneal macrophages (PM) were measured by RIA. Intragastric administration of hesperidin significantly attenuated secondary paw swelling and reduced the polyarthritis index of AA rats in a dose-dependent manner. In addition, hesperidin clearly ameliorated the pathological changes in AA rats. Hesperidin also restored the suppression of T-lymphocyte proliferation and IL-2 production, and downregulated production of IL-1, IL-6 and TNF-α by PM in AA rats. Our results suggest that hesperidin improves AA by downregulating the function of over-active macrophages and by up-regulating the activities of dysfunctional T lymphocytes. Hesperidin may therefore have therapeutic value for the clinical treatment of RA. Further research is required to clarify the detailed mechanisms of the protective effects of hesperidin on AA.

Inflammation is preceded by tumor necrosis factor-dependent infiltration of mesenchymal cells in experimental arthritis

OBJECTIVE

To determine the involvement of mesenchymal progenitor cells in the induction of collagen-induced arthritis (CIA).

METHODS

DBA/1 mice were immunized with type II collagen in adjuvant or adjuvant alone, and the presence of mesenchymal cells in the joints of prearthritic mice was studied by immunohistochemistry.

RESULTS

An analysis of the joints on day 10 postimmunization (at least 10 days before the onset of arthritis) revealed synovial hyperplasia without leukocytic infiltration. Large, round cells expressing bone morphogenetic protein receptors (BMPRs), which serve as markers for primitive mesenchymal cells, were present in increased numbers in the bone marrow adjacent to the joint, in the synovium itself, and within enlarged bone canals that connect the bone marrow to the synovium. Similar changes were observed in mice given adjuvant without collagen. Adjuvant-induced infiltration of BMPR(+) cells and enlargement of bone canals were abrogated by anti-tumor necrosis factor (anti-TNF) treatment and were absent in TNFR p55/p75(-/-) mice. Increased numbers of bone marrow cells and enlarged bone canals were observed in nonimmunized TNF transgenic mice (which spontaneously develop arthritis).

CONCLUSION

These findings suggest that in CIA, there is an antigen-independent (innate) prearthritic phase that prepares the joint for the subsequent immune-mediated arthritis. The induction phase involves marrow-derived mesenchymal cells and requires the presence of TNF.

Bone abnormalities in the surgical treatment of patients with rheumatoid arthritis

Profound abnormalities of bone are an important component of the morbidity of rheumatoid arthritis and partly determine the orthopaedic treatment of patients. The principal bone abnormality, which is osteoporosis associated with rapid remodeling, degrades the mechanical properties of the skeleton in juxtaarticular bone, in the diaphyses of long bones, in the pelvis, and in the base of skull. Abnormalities of bone affect clinical decision making in the surgical treatment of patients with rheumatoid arthritis and must be considered for the optimal treatment of these patients. Increased fracture risk and compromised bony fixation complicate fracture treatment. Techniques of surgery must be modified to protect bone from intraoperative fracture. Methods of fixation of implants and other devices must be appropriate to the biomechanics of the bone. Bone healing usually is rapid if not compromised by mechanical instability. Specific patterns of bone deformation and failure can be identified in the evolution of rheumatoid arthritis. Bone graft used in reconstruction of the protruded acetabulum is incorporated rapidly. Bone resorption with joint instability is a common feature of rheumatoid arthritis; however, the opposite pattern of bony ankylosis with stiffness is observed in a smaller percentage of patients. Recognition of the tissue type is necessary for the individualization of surgical procedures to achieve optimal joint stability and mobility. Based on growing understanding of the pathophysiology of bone in patients with rheumatoid arthritis, new pharmacologic therapies may become available for the prevention and treatment of bone abnormalities in patients with rheumatoid arthritis.

Dexamethasone prevents the decrease of bone mineral density in type II collagen-induced rat arthritis model

This study demonstrated the decrease of bone mineral density (BMD) in the type II collagen (CII)-induced arthritis (CIA) model in rats and the relationship between BMD and paw edema and the effect of dexamethasone-21-phosphate (DEX). The paw swelling occurred on Day 10 and reached its peak on Day 18 after CII injection. BMD in the CII-injected group is lower than that in the control group. BMD in the proximal and distal regions of the femur largely decreased in comparison with that of the middle region. The oral administration of DEX (0.1 mg/kg) inhibited the swelling and decrease of BMD in all three regions of the femur.