We aimed to investigate the effects of an anti-tumor necrosis factor-α antibody (ATNF) on cartilage and subchondral bone in a rat model of osteoarthritis. Twenty-four rats were randomly divided into three groups: sham-operated group (n=8); anterior cruciate ligament transection (ACLT)+normal saline (NS) group (n=8); and ACLT+ATNF group (n=8). The rats in the ACLT+ATNF group received subcutaneous injections of ATNF (20 μg/kg) for 12 weeks, while those in the ACLT+NS group received NS at the same dose for 12 weeks. All rats were euthanized at 12 weeks after surgery and specimens from the affected knees were harvested. Hematoxylin and eosin staining, Masson's trichrome staining, and Mankin score assessment were carried out to evaluate the cartilage status and cartilage matrix degradation. Matrix metalloproteinase (MMP)-13 immunohistochemistry was performed to assess the cartilage molecular metabolism. Bone histomorphometry was used to observe the subchondral trabecular microstructure. Compared with the rats in the ACLT+NS group, histological and Mankin score analyses showed that ATNF treatment reduced the severity of the cartilage lesions and led to a lower Mankin score. Immunohistochemical and histomorphometric analyses revealed that ATNF treatment reduced the ACLT-induced destruction of the subchondral trabecular microstructure, and decreased MMP-13 expression. ATNF treatment may delay degradation of the extracellular matrix via a decrease in MMP-13 expression. ATNF treatment probably protects articular cartilage by improving the structure of the subchondral bone and reducing the degradation of the cartilage matrix.

A atividade antioxidante, a toxicidade geral e a citotoxidade dos extratos metanólicos de Centaurea urvillei subs. armata e C. mucronifera foram analisados, respectivamente, pelo ensaio DPPH e pelos ensaios de letalidade de Artemia salina e de citotoxidade MTT. A análise dos extratos metanólicos em CLAE de fase reversa apresentou duas lignanas biotivas do tipo dibenzilbutirolactona, matairesinosídeo (1) e arctiina (2). As estruturas destas lignanas foram elucidadas através de análises espectroscópicas completas bem como por comparação direta dos dados experimentais com os respectivos dados da literatura.

The antioxidant activity, general toxicity and cytotoxicity of the methanol extracts of Centaurea urvillei subs. armata and C. mucronifera have been assessed, respectively, by the DPPH assay, the brine shrimp lethality and the MTT cytotoxicity assays. The reversed-phase HPLC analysis of the methanol extracts afforded two bioactive dibenzylbutyrolactone-type lignans, matairesinoside (1) and arctiin (2). The structures of these lignans were elucidated by comprehensive spectroscopic analyses as well as by the direct comparison of experimental data with respective literature data.