Chitosan oligosaccharides inhibit IL-1β-induced chondrocyte apoptosis via the P38 MAPK signaling pathway.

The preventive and therapeutic effects of chitosan oligosaccharides (COS) on osteoarthritis (OA) have been rarely investigated. In this study, the protective effects of COS against IL-1β-induced chondrocyte apoptosis were evaluated and the underlying mechanisms were elucidated. Results showed that COS not only inhibited cell apoptosis in a dose-dependent manner but also ameliorated IL-1β-induced nuclear chromatin damage and mitochondrial membrane potential in chondrocytes. In IL-1β-treated chondrocytes, COS downregulated the expression of Bax and caspase-3 but upregulated the expression of Bcl-2 by inhibiting the phosphorylated p38 mitogen-activated protein kinase (MAPK). COS inhibited the mRNA expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase-13 (MMP-13) and enhanced the mRNA expression of the tissue inhibitor of metalloproteinase-1 (TIMP-1). These results suggested that COS effectively inhibits the IL-1β-induced apoptosis of chondrocytes by activating the p38 MAPK signaling pathway. COS may also be used as a unique biological agent to prevent and treat OA.