| Summary: | Osteoarthritis is characterized by cartilage loss resulting from the activation of chondrocytes associated with a synovial inflammation. Activated chondrocytes promote an increased secretion of matrix proteases and proinflammatory cytokines leading to cartilage breakdown. Since natural products possess anti-inflammatory properties, we investigated the direct effect of <i>Rubus idaeus</i> extracts (RIE) in chondrocyte metabolism and cartilage loss. The effect of RIE in chondrocyte metabolism was analyzed in murine primary chondrocytes and cartilage explants. We also assessed the contribution of RIE in an inflammation environment by culturing mice primary chondrocytes with the supernatant of Raw 264.7 macrophage-like cells primed with RIE. In primary chondrocytes, RIE diminished chondrocyte hypertrophy (<i>Col10</i>), while increasing the expression of catabolic genes (<i>Mmp-3</i>, <i>Mmp-13)</i> and reducing anabolic genes (<i>Col2a1</i>, <i>Acan</i>). In cartilage explants, <i>Rubus idaeus</i> prevented the loss of proteoglycan (14.84 ± 3.07% loss of proteoglycans with IL1 alone vs. 3.03 ± 1.86% with IL1 and 100 µg/mL of RIE), as well as the NITEGE neoepitope expression. RIE alone reduced the expression of <i>Il1</i> and <i>Il6</i> in macrophages, without changes in <i>Tnf</i> and <i>Cox2</i> expression. The secretome of macrophages pre-treated with RIE and transferred to chondrocytes decreases the gene and protein expression of <i>Mmp-3</i> and <i>Cox2</i>. In conclusion, these data suggest that RIE may protect from chondrocyte catabolism and cartilage loss in inflammatory conditions. Further evaluations are need before considering RIE as a candidate for the treatment for osteoarthritis.
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