Clematis mandshurica protected to apoptosis of rat chondrocytes

To investigate the effect of SKI 306X, a purified extract from the mixture of three herbs, i.e. Clematis mandshurica, Trichosanthes kirilowii and Prunella vulgaris, on apoptosis in chondrocytes. Rat chondrocyte cell line RCJ3.1C.18 cells were incubated with 1 μM staurosporin and SKI 306X or each of its components. Cell viability was determined by trypan blue exclusion assay. Induction of apoptosis was determined by nuclear condensation or fragmentation after Hoechst staining. Amount of apoptosis was quantified both by nuclear morphology and flow cytometry. Expression level of Bcl-2, and caspase-3 and PARP activations were assayed by Western blot. SKI 306X significantly prevented staurosporin-induced apoptosis. Among its three components, only Clematis mandshurica significantly decreased the amount of staurosporin-induced apoptosis. Although the level of Bcl-2 expression was decreased after staurosporin treatment, it was sustained after the combination treatment with Clematis mandshurica. Whereas staurosporin induced the degradation of 32 kDa caspase-3 precursor and the production of 85-kDa cleavage products of PARP in a time-dependent fashion, Clematis mandshurica treatment prevented those manifestations. Pharmacological efficacy of SKI 306X protecting osteoarthritis in part may result from the inhibition of apoptosis in chondrocytes by Clematis mandshurica.