In rheumatoid arthritis, the inhibitory effect of lipopolysaccharide (LPS) on IL-10 expression in fibroblast-like synoviocytes can be significantly reversed by shikonin due to the inactivation of the PKC-NF-κB pathway, thereby reducing the production of tumor necrosis factor-α (TNF-α) [18]. Here, TNF is linked to rheumatoid arthritis.