Search

It is well known that the inflammatory cytokines play important roles in osteoarthritis (OA). In the present study, we investigated the anti-inflammatory properties of morin in chondrocytes. The nitric oxide (NO) production was determined by Griess method, the prostaglandin E2 (PGE(2)) production was detected by Enzyme-linked immunosorbent assay (ELISA). The expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 were investigated by quantitative real-time PCR and western blot. In addition, western blotting and immunofluorescence staining were performed to investigate the protein level of inhibitor of nuclear factor-κB (IκB-α) and the translocation of nuclear factor kappa B (NF-κB). For the in vivo study, morin was administered by intra-articular injection in rats, and the gene expression of iNOS and COX-2 was assessed. We showed that morin inhibited the production of NO and PGE(2) as well as the expression of iNOS and COX-2 in interleukin-1-beta (IL-1β)-induced chondrocytes. In addition, morin suppressed the degradation of IκB-α as well as the translocation of NF-κB. In vivo study, morin exerted anti-inflammatory properties in an IL-1β-induced rat OA model. Our data suggest that morin possess potential value in the treatment of OA.

Thymoquinone (TQ) is the main constituent of Nigella sativa oil, which has been traditionally used against arthritis in the Middle East. In this study, we investigated the effect of TQ against matrix metalloproteinase (MMP) expression in both rabbit chondrocytes and animal mode of osteoarthritis (OA) induced by anterior cruciate ligament transection and tested whether or not nuclear factor kappa B (NF- κB) was involved in this process. TQ down-regulated MMP-1, MMP-3 and MMP-13 expression and up-regulated tissue inhibitors of metalloproteinase-1 expression as assessed by quantitative realtime polymerase chain reaction. In addition, NF- κB p65 protein level as well as its translocation induced by interleukin-1 β were inhibited by TQ. Our findings suggest the potential of TQ in the treatment of OA.

Apelin is a recently discovered hormone secreted by adipocytes. The aim of this study, therefore, was to evaluate the distribution of apelin in paired serum and synovial fluid (SF) of osteoarthritis (OA) patients, as compared to that in healthy controls, and to characterise the expression profile of apelin and its cognate receptor APJ in human chondrocytes. Apelin levels in serum and SF were analysed by enzyme-linked immunosorbent assay (ELISA). Expression of apelin and APJ in human chondrocytes was determined by real-time quantitative polymerase chain reaction (PCR). Apelin was found to be present in OA SF, and concentrations were positively correlated with the severity of OA. OA serum exhibited significantly elevated levels of apelin (2.18 ± 0.22 ng/ml) as compared to normal serum (1.31 ± 0.12 ng/ml) (p

Diallyl sulphide (DAS) is known for its antioxidant, anticancer and detoxifying properties. The aim of this study was to investigate the effect of DAS on rabbit articular chondrocytes and cartilage in experimental osteoarthritis (OA) induced by anterior cruciate ligament transection (ACLT). DAS inhibited matrix metalloproteinase-1 (MMP-1), MMP-3 and MMP-13 expression in interleukin-1beta (IL-1β)-induced chondrocytes. In an in vivo study, DAS ameliorated cartilage degradation as assessed by morphological and histological examination. Messenger RNA expression of MMP-1, MMP-3, MMP-13 and IL-1β was inhibited by DAS in cartilage. In addition, DAS increased the collagen II level in cartilage. The results suggest that DAS may protect cartilage in the development of OA.

Cartilage degradation is one of the pathological changes of osteoarthritis (OA), and accumulating evidence suggests an excess of matrix metalloproteinases (MMPs) plays a role in this cartilage breakdown. Here, we investigated the effects of chlorogenic acid (CGA) on the mRNA and protein expression of MMPs in interleukin (IL)-1β-induced rabbit chondrocytes and evaluated the in vivo effects of CGA in experimental OA induced by anterior cruciate ligament transection (ACLT) in rabbits. Using quantitative real-time PCR and ELISA to investigate the expression levels of MMP-1, MMP-3, MMP-13, and tissue inhibitors of metalloproteinase-1(TIMP-1) in IL-1β-induced rabbit chondrocytes, we showed that CGA inhibits the expression of these MMPs while increasing TIMP-1 expression, at both the mRNA and protein levels. In addition, IL-1β-induced activation of nuclear factor kappa B (NF-κB) and the degradation of inhibitor of κB (IκB)-α were suppressed by CGA. In rabbits, CGA decreased cartilage degradation as assessed by morphological and histological analyses. The down-regulation of MMP-1, MMP-3, and MMP-13 expression and up-regulation of TIMP-1 expression were also detected in CGA-treated cartilage compared with vehicle-treated cartilage, confirming these findings in an in vivo model. Taken together, these findings indicate that CGA may be considered as a possible candidate agent in the treatment of OA.

Adipokines play key roles in the regulation of bone growth, obesity, diabetes mellitus type 2, and HIV infection. As a newly discovered hormone in the adipokine family, the precise role of apelin on articular cartilage metabolism is not yet clear. The aim of this study was to evaluate the role of apelin on articular cartilage. In vitro, we examined the effects of apelin on normal chondrocyte proliferation and gene expression of metalloproteinases (MMPs) and interleukin-1beta (IL-1beta). In vivo, by intra-articular injection with apelin, we examined MMP-3, -9, collagen II and IL-1beta at both gene and protein levels. Furthermore, we measured the messenger RNA (mRNA) expression of ADAMTS-4 and -5 (a disintegrin and metalloproteinase with thrombospondin motifs 4 and 5) and the proteoglycan content in articular cartilage. Apelin stimulated the proliferation of chondrocytes and significantly increased mRNA levels of MMP-1, -3, -9 and IL-1beta in vitro. Intra-articular injection with apelin in vivo up-regulated the expression of MMP-3, -9, and IL-1beta as well as decreased the level of collagen II. Additionally, after treatment with apelin, mRNA levels of ADAMTS-4 and -5 markedly increased and depletion of proteoglycan in articular cartilage was found by histological assessment. These findings suggest that apelin plays a catabolic role in cartilage metabolism and is a risk factor in the pathophysiology of osteoarthritis.

Berberine shows anticancer, antibacterial, antiinflammatory and antioxidant effects and may be useful in many clinical applications. The effects of berberine on articular cartilage metabolism remain unknown, so this study was performed to evaluate these effects in vitro and in vivo. For the in vitro work, rat articular chondrocytes were cultured in a monolayer and matrix metalloproteinase-1 (MMP-1), -3, -13 and tissue inhibitor of metalloproteinase (TIMP-1) expression was evaluated by real-time quantitative PCR. Nitric oxide (NO) levels were determined using the Griess reaction, and glycosaminoglycan (GAG) release was measured using the dimethylmethylene blue method. For the in vivo work, berberine was administered by intraarticular injection, and the effects on MMPs and TIMP-1 were examined at the gene and protein levels. Berberine was found to inhibit the expression of MMP-1, -3 and -13, and increased the level of TIMP-1 at the mRNA level in a dose-dependent manner. In IL-1β-induced rat articular chondrocytes, berberine decreased IL-1β-induced GAG release and NO production. Meanwhile, high-dose berberine exhibited an anticatabolic effect in an IL-1β-induced rat osteoarthritis (OA) model. These findings suggest that berberine may play a protective role in the development of OA and may be useful in the treatment of OA.