shikonin and Osteoarthritis

Osteoarthritis (OA) is a chronic joint degenerative disease characterised by narrowed articular space, formation of surrounding osteophytes, and subchondral bone sclerosis. OA is caused by cartilage degeneration, which is closely correlated with the disequilibrium of anabolism and catabolism in chondrocytes. Previous studies have revealed that autophagy plays a significant role in maintaining the balance of anabolic and catabolic activities. Thus, targeting autophagy may be a promising therapeutic strategy for OA. Shikonin, a traditional Chinese herbal medicine isolated from flavonoid glucuronide, has drawn focus for its role in activating autophagy. In this study, the mRNA and protein level of a disintegrin and metalloproteinase with thrombospondin motifs-5 and matrix metalloproteinases-1 decreased with shikonin treatment, in the IL-1β-induced OA cell model. On the contrary, IL-1β-induced downregulation of Aggrecan and Collagen II was ameliorated following shikonin treatment. In addition, the upregulation of autophagy-related marker genes Beclin-1 and LC3II/LC3I in chondrocytes indicated that autophagy could be activated upon shikonin treatment. Moreover, shikonin's promotion of anabolism in chondrocytes through autophagy activation corresponded with the results from the examination using chloroquine, an autophagy inhibitor. OA mouse cartilage tissues were stained with safranin O and fast green dyes. Results were analysed using the Osteoarthritis Research Society International (OARSI) score, and suggested that mice cartilage degeneration was alleviated after shikonin treatment. Altogether, we identified that shikonin might be a novel promising drug for OA treatment.

Topics: Animals; Autophagy; Cartilage, Articular; Cells, Cultured; Chondrocytes; Interleukin-1beta; Mice; Naphthoquinones; Osteoarthritis

Topics: Cartilage, Articular; Cells, Cultured; Chondrocytes; Humans; Inflammation; Naphthoquinones; Osteoarthritis

Shikonin, a natural product from Lithospermum erythrorhizon, exerts a wide range of anti-inflammatory actions both in vitro and in vivo. Matrix metalloproteinases (MMPs) have long been considered as the major catabolic enzymes involved in osteoarthritis (OA) cartilage erosion. Here, we investigated the anti-inflammatory and effects of shikonin on MMPs in both IL-1β induced rabbit chondrocytes and the experimental rabbit OA model induced by anterior cruciate ligament (ACL) transection and evaluated the potential involvement of nuclear factor kappa B (NF-κB) in the processes. In vitro, rabbit chondrocytes were cultured and pretreated with shikonin (0, 1, 5, 10μM) for 1h (h) with or without IL-1β (10ng/ml) for 24h. The expression of MMPs (MMP-1, MMP-3 and MMP-13) and tissue inhibitors of metalloproteinase-1 (TIMP-1) at mRNA and protein levels were determined by quantitative real-time PCR and ELISA respectively. NF-κB related signaling molecules were investigated by Western blotting. In vivo study, the effects of shikonin on MMPs and TIMP-1 were determined at the gene level and the cartilage damage was evaluated at the histological level after the rabbits sacrificed. We found that shikonin significantly reversed the elevated expression of MMP-1, MMP-3 and MMP-13 and the reduced expression of TIMP-1 at both gene and protein levels in IL-1β induced chondrocytes. Additionally, the reduction of IκBα and the activation of NF-κB p65 induced by IL-1β were subsided by shikonin in rabbit chondrocytes. In vivo, both the cartilage damage and the elevated expression of MMP-1, MMP-3 and MMP-13 and the decreased expression of TIMP-1 were ameliorated in shikonin intra-articular injection knees compared to vehicle knees. Our findings indicated that shikonin have anti-inflammatory and chondro-protective effects and may be a potential therapeutic agent for the treatment of OA.

Topics: Animals; Cartilage; Cell Survival; Chondrocytes; Gene Expression Regulation; I-kappa B Kinase; Inflammation; Interleukin-1beta; Male; Matrix Metalloproteinases; Naphthoquinones; NF-kappa B; Osteoarthritis; Rabbits; Tissue Inhibitor of Metalloproteinase-1