Brazilin blocks catabolic processes in human osteoarthritic chondrocytes via inhibition of NFKB1/p50.

This study aimed to evaluate the chondroprotective and anti-inflammatory activity of brazilin in human osteoarthritic (OA) cartilage and chondrocytes with particular focus on the nuclear factor-kappa B (NF-B) pathway. Therefore, brazilin was isolated from Caesalpinia sappan and identified using high performance liquid chromatography (HPLC). The effect of brazilin was assessed in cartilage explants treated with 10ng/ml interleukin (IL)-1 and 10ng/ml tumor necrosis factor (TNF)- using histological and biochemical glycosaminoglycan (GAG) analyses and in primary chondrocytes treated with 10ng/ml IL-1 using RT-qPCR, ELISA, and Western blot. The involvement of NF-B signaling was examined using a human NF-B signaling array and in silico pathway analysis. Brazilin was found to reduce the GAG loss from cartilage explants stimulated with IL-1 and TNF-. NF-B pathway analysis in chondrocytes revealed NFKB1/p50 as a central player regulating the anti-inflammatory activities of brazilin. Brazilin suppressed the IL-1-mediated up-regulation of OA markers and the induction of NFKB1/p50 in chondrocytes. In conclusion, brazilin effectively attenuates catabolic processes in human OA cartilage and chondrocytesat least in part due to the inhibition of NFKB1/p50which indicates a chondroprotective potential of brazilin in OA. (c) 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2431-2438, 2018.