Altered Aggrecan Synthesis and Collagen Expression Profiles in Chondrocytes from Patients with Kashin-Beck Disease and Osteoarthritis

OBJECTIVES: To investigate cell morphology, aggrecan expression, and type I, II, III and X collagen expression in chondrocytes from adults with Kashin-Beck disease or osteoarthritis (OA). METHODS: Samples of knee articular cartilage were taken during surgery; cartilage samples obtained from fresh cadavers without arthritic disease were used as controls. Samples were digested with collagenase; isolated chondrocytes were cultured in monolayers. Aggrecan was detected by toluidine blue staining; collagen and aggrecan protein levels were evaluated by immunocytochemistry and immunofluorescence staining. RESULTS: Samples were obtained from six participants per group. Aggrecan and type II collagen levels in chondrocytes from patients were significantly lower than those from controls, but levels of type I, III and X collagen were enhanced in patients compared with controls. Production of type III and X collagen was higher in chondrocytes from patients with Kashin-Beck disease than in those from OA patients. CONCLUSIONS: Biochemical and morphological mechanisms underlying Kashin-Beck disease and OA include enhanced dedifferentiation and hypertrophy of chondrocytes, increased type I, III and X collagen levels, and suppressed type II collagen and aggrecan production compared with control samples.