OBJECTIVETo investigate chondrocyte apoptosis and expression of Fas and inducible nitric oxide synthase (iNOS) in articular cartilage in the pathogenesis of Kashin-beck disease (KBD) and primary osteoarthritis (OA).

METHODSThe collected samples of articular cartilage were divided into three groups: normal control (15 cases), KBD adults (15 cases) and OA (15 cases). Chondrocyte apoptosis was detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling method, and Fas and iNOS in articular cartilage were stained by immunohistochemistry.

RESULTSThe positive percentages of chondrocyte apoptosis stained in articular cartilage of KBD and OA were significantly higher than that of the control (P < 0.01), and the positive percentage of chondrocytes apoptosis in the eroded areas of articular cartilage were significantly higher than in the non-eroded areas in articular cartilage of the same patient with KBD and OA (P < 0.05). There was no significant difference in positive percentage of chondrocytes apoptosis between KBD and OA. The positive percentages of Fas and iNOS in chondrocytes were significantly higher in KBD and OA than in control (P < 0.01). Significant differences in Fas and iNOS expression between the eroded areas and non-eroded areas were seen in articular cartilage of patients with KBD and OA (P < 0.05), but such difference did not exist between KBD and OA.

CONCLUSIONCell apoptosis seems to be associated with the pathogenesis of both KBD and OA. Fas and iNOS might mediate chondrocyte apoptosis.