Stimulating effect of a newly synthesized sulfonamido-based gallate on articular chondrocytes in vitro

The phenotype of chondrocyte is easy to be lost when expanded in vitro by a process defined "dedifferentiation". Traditional growth factors such as transforming growth factor (TGF-β1) are effective in preventing of dedifferentiation, but high costs and loss of activity limited their use. It is of significance to find substitutes which can reduce dedifferentiation and preserve chondrocytes phenotype to ensure sufficient differentiated cells for further study.

We synthesized new type of sulfonamido-based gallates named ZXHA-C and investigated its effect on primary articular chondrocytes of rats. After preliminary screening by cytotoxicity test, ZXHA-C of 1.06 × 10-8, 1.06 × 10-7 and 1.06 × 10-6M were chosen for further studies. Cell proliferation, morphology, viability, GAG synthesis and cartilage specific gene expression were detected. Also the effects of ZXHA-C on Wnt/β-catenin signaling pathway were investigated.

ZXHA-C could significantly promote chondrocytes growth. And it could enhance ECM synthesis by up-regulating expression levels of cartilage specific markers like aggrecan, collagen II and Sox9. Expression of collagen I which marked chondrocytes dedifferentiation was also significantly down-regulated after treated by ZXHA-C. Further exploration of the molecular mechanism indicated that ZXHA-C activated the Wnt/β-catenin signal pathway in chondrocytes, as evidenced by up-regulated gene expression of β-catenin, Wnt-4, cyclin D1 and Frizzled-2 and decreased glycogen synthase kinase 3β (GSK-3β). Among the various concentrations, ZXHA-C of 1.06 × 10-7 M showed the best performance, which was close to positive control (group with TGF-β1).

ZXHA-C might be potential a novel agent for the maintenances of chondrocytes phenotype.