• M Akagi, A Ueda, T Teramura, S Kanata, T Sawamura, and C Hamanishi.
• Department of Orthopaedic Surgery, Kinki University School of Medicine, Osaka-Sayama City, Osaka, Japan. makagi@med.kindai.ac.jp
• Osteoarthr. Cartil. 2009 Feb 1; 17 (2): 271-5.

ObjectiveIt has been suggested that oxidized low-density lipoprotein (ox-LDL) has some roles in progression of osteoarthritis. The purpose of this study is to investigate whether ox-LDL binding to lectin-like ox-LDL receptor 1 (LOX-1) enhances monocyte chemoattractant protein 1 (MCP-1) expression in cultured human articular chondrocytes (HACs).MethodThe time course and dose response of MCP-1 mRNA expression and MCP-1 protein release into medium following ox-LDL stimulation were investigated using quantitative Real time PCR (delta-delta Ct method) and enzyme-linked immunosorbent assay (ELISA), respectively. To examine the receptor specificity of ox-LDL action, HACs were preincubated with anti-human LOX-1 monoclonal antibody (TS92).ResultsA time-course study revealed that MCP-1 mRNA expression increased 5.09+/-0.86 fold 12h after ox-LDL stimulation compared to time-0. ox-LDL stimulation increased MCP-1 protein level in conditioned medium in a time-dependent manner. Increased MCP-1 level was evident 6h after stimulation, reaching 830+/-91 pg/ml at 24h (33+/-8 pg/ml at time-0). Dose responses of MCP-1 expression were also evident in mRNA and protein levels. Pretreatment with TS92 markedly suppressed these stimulating effects of ox-LDL, although that with non-specific IgG did not. Native LDL did not affect MCP-1 expression.ConclusionOur results suggest that ox-LDL enhances MCP-1 expression in HACs and supports the hypothesis that ox-LDL is involved in cartilage degeneration.

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