Abstract: Objective To study the effect of ecdysterone (EDS) on rabbits chondrocytes that is injuried by lipopolysaccharide (LPS). Methods Aricular chondrocytes were isolated from rabbits and randomly divided into three groups: control group; chondrocytes with LPS induced injury (LPS group); injury chondrocytes treated with EDS (LPS+EDS group). The cell proliferation and cell apoptosis of chondrocytes were determined by MTT method and flow cytometry assay respectively. The mRNA and protein expression levels of inducible nitric oxide synthase (iNOS) were detected by RT-PCR and western blot.In addition, the content of NO and IL-1β were measured by nitric acid reductase assay and enzyme-linked immunosorbent assay (ELISA) respectively. Results Attenuated proliferation, increased cell apoptosis, iNOS, NO and IL-1β were seen in LPS group , but all these changes were significantly reversed by EDS treatment (P < 0.05). Conclusion Ecdysterone exhibited a protective effect on LPS induced rabbits chondrocytes injury through inhibiting the expression of iNOS.

Key words: Ecdysterone, chondrocytes, lipopolysaccharides, cell proliferation, apoptosis, interleukin-1beta, iNOS