Objective To assess whether interleukin-10 (IL-10) is chondropotective in vitro. Methods Chonrocytes Ⅱ. The first passage cells were grown in 24-well plates with DMEM, supplemented with 10% fetal bovine serum, for 2-4 days. The cells were then cultured in 0.1% fetal bovine serum DMEM medium, and given respecitvly interleukin-1 (IL-1) 100μ/ml, IL-1 100μ/ml +recombinant murine interleukin-10 (mnIL-10) 20ng/ml, mmIL-10 20ng/ml, and cultured for 48 hours. Scanning electron morphology and immunohistochemical study of nitric oxide synthease 2 and matric metalloproteinase 3 mRNA in situ hybridization were performed. Cell proliferation and morphology were observed under inverted microscope from the beginning of cell culture for three weeks. Results IL-1 stimulated granule production in the cytoplasma of chondrocytes, and the cells died in the second third weeks of culture. IL-10 antagonized IL-1, protected the cells from death and maintained chondrocyte proliferation. scanning electron morphology showed that IL-1 stimulated the formation of mumerous microvilli on the cell surface, while thin and less numerous microvilli were found in culturre with IL-10. Immunohistochemical study and in situ hybridization showed that IL-10 inhibited NOS2 and MMP3 expression. Conclusion IL-10 not only inhibits the synthesis of inflammatiory cytokines, but also directly protects chondrocytes by antagonizing IL-1.