PMC:17821 / 37596-39766 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/17821","sourcedb":"PMC","sourceid":"17821","source_url":"http://www.ncbi.nlm.nih.gov/pmc/17821","text":"FcγR expression on macrophages is correlated with cartilage destruction during immune-complex-mediated arthritis\nApart from inflammation, absence or overexpression of FcγRs by local macrophages may also have serious consequences for cartilage destruction. We investigated several parameters of cartilage destruction (depletion of proteogly-cans [PGs], chondrocyte death, and erosion of the cartilage matrix). Arthritic knee joints of the three strains were compared at different time points after ICA induction. At day 3, control C57BL/6 mice showed marked PG depletion in various cartilage surfaces (patella, femur adjacent to patella, lateral and medial condyle of the femur, and lateral and medial condyle of the tibia). Strikingly, PGs were not depleted in arthritic knee joints of the FcR γ-chain-/- mice (Fig. 6a,b; Table 4). In contrast, arthritic DBA/1 knee joints showed markedly greater depletion of PGs than those of C57BL/6 mice. Moreover, PG depletion was still severe at days 7 and 14 in the DBA/1 mice, whereas in the C57BL/6 mice it was almost fully restored by day 14 (Fig. 6b-e; Table 4). When ICA was induced in FcR γ-/- mice with a DBA/1 background, PG depletion at day 3 was scored 2.6 ± 0.3 in the Fcγ-chain+/+ mice and was totally absent in the FcR γ-chain-/- ones.\nChondrocyte death was measured by determining empty lacunae in the cartilage matrix and breaks in DNA strands as evaluated using an in situ cell detection kit (TUNEL method; data not shown). In knee joints of C57BL/6 mice, chondrocyte death at day 3 was 5% in the patella and 30% in the adjacent femur. In the knee joints of knockout mice, chondrocyte death was completely absent (Table 4), whereas in the DBA/1 mice, it was strikingly higher in both the patella (50%) and the femur (90%) than in the control mice (C57BL/6).\nFinally, erosion of the cartilage matrix in knee joints was measured. Whereas no erosion was found in either FcR γ-chain-/- or C57BL/6 mice at day 3 after arthritis induction, in DBA/1 mice erosion was already considerable by day 3, and complete loss of the cartilage surface layer up to the tidemark was observed at days 7 and day 14 (Fig. 6d,e; Table 4).","divisions":[{"label":"Title","span":{"begin":0,"end":112}}],"tracks":[]}