[Expression of Caspase-8 and Bcl-2 in the cartilage loose bodies in patients with Kashin-Beck disease].

OBJECTIVE

To investigate the role of Caspase-8 and Bcl-2 in the formation of loose bodies in Kashin-Beck disease (KBD).

METHODS

Specimens of cartilage loose bodies were collected from 50 adult patients with KBD, and the samples of articular cartilage were collected from 10 healthy adults to serve as control. Avidin-biotin alkaline phosphatase immunohistochemistry was employed to examine Bcl-2 and Caspase-8 positivities in the chondrocytes in the loose bodies.

RESULTS

In KBD loose bodies, the percentage of chondrocytes positive for Bcl-2 and Caspase-8 [(18.40∓8.78)% and (67.54∓12.29)%, respectively] were significantly higher than those of the control group [(12.25∓1.58)% and (24.70∓4.35)%, respectively]. Caspase-8 was found to promote chondrocyte apoptosis in the loose bodies, and this effect overrode the apoptosis-suppressing effect of Bcl-2. Bcl-2 and Caspase-8 positivities were found mainly in the deep hypertrophic chondrocytes in the cartilage or in cells adjacent to the bone tissues.

CONCLUSION

KBD loose bodies contain an increased percentage of apoptotic chondrocytes positive for Bcl-2 and Caspase-8. The apoptosis-inducing effect of Caspase-8 was a dominant feature in the cartilage pathology of KBD compared to the apoptosis-suppressing effect of Bcl-2.