Lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) expression in human articular chondrocytes

• Published in: Clinical and experimental rheumatology 2007-07, Vol.25 (4), p.605-612
• Main Authors: SIMOPOULOU, T, MALIZOS, K. N, TSEZOU, A
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Ascorbic Acid - pharmacology; Biological and medical sciences; Cartilage, Articular - chemistry; Cartilage, Articular - cytology; Cell Survival; Chondrocytes - chemistry; Diseases of the osteoarticular system; Female; Fluorescent Antibody Technique; Humans; Lipoproteins, LDL - analysis; Lipoproteins, LDL - pharmacology; Male; Medical sciences; Middle Aged; Miscellaneous. Osteoarticular involvement in other diseases; Osteoarthritis; Osteoarthritis - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - analysis; Scavenger Receptors, Class E - analysis; Scavenger Receptors, Class E - genetics; Scavenger Receptors, Class E - physiology; Synovial Fluid - chemistry
• ISSN: 0392-856X; 1593-098X

To investigate the involvement of oxidized low density lipoprotein (ox-LDL) and the expression of its receptor lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) in osteoarthritis, by determining the ox-LDL in synovial fluid and the expression of LOX-1 mRNA and protein in osteoarthritic as well as normal cartilage. In addition, the effect of ox-LDL on chondrocyte viability and the effect of ascorbic acid (a well-known anti-oxidant) on LOX-1 expression were studied. Fifteen patients were included in the study. Osteoarthritic articular cartilage was obtained from two distinct locations in the knee (n = 10) and hip (n = 5), specifically from weight-bearing and non-weight-bearing areas of the same joints. Five individuals were used as controls. mRNA and protein expression were studied by RT-PCR and immunofluorescence, respectively. Ox-LDL was measured in the synovial fluid and in paired serum samples from the patients using the ELISA method. Ox-LDL was detected in the synovial fluid and its receptor LOX-1 was detected in cartilage from both weight-bearing and non-weight-bearing areas, whereas no LOX-1 expression was found in normal cartilage. Ox-LDL reduced chondrocyte viability in cell cultures, while the addition of ascorbic acid to osteoarthritic chondrocytes resulted in a decrease in LOX-1 mRNA expression. The detection of LOX-1 mRNA and protein expression in osteoarthritic cartilage drawn from both weight-bearing and non-weight-bearing regions of the same patients suggest that LOX-1 may be involved in the progression and pathogenesis of osteoarthritis.