Cynaroside protects human periodontal ligament cells from lipopolysaccharide-induced damage and inflammation through suppression of NF-κB activation

Objective: To investigate whether cynaroside protects human periodontal ligament (hPDL) cells from lipopolysaccharide (LPS)-induced damage and inflammation and to analyze the underlying mechanism. Methods: LPS was used to stimulate hPDL and RAW264.7 cells. MTT assay was used to detect cell viability, and protein expression levels were measured via western blot analysis. Nitrite oxide and prostaglandin E-2 were used to quantify the inflammatory response. Alizarin Red S staining was used to detect mineralized nodules. Results: Cynaroside inhibited the expression of iNOS, COX-2, TNF-alpha, and IL-6 in LPS-stimulated hPDL and RAW264.7 cells without cytotoxicity. Furthermore, cynaroside significantly suppressed LPS-induced protein expression of matrix metalloproteinase 3. Additionally, cynaroside prevented LPS-induced NF-kappa B p65 subunit translocation to the nucleus by inhibiting the phosphorylation and degradation of I kappa B-alpha. Moreover, cynaroside could restore the mineralization ability of hPDL cells reduced by LPS. Conclusion: Cynaroside protected hPDL cells from LPS-induced damage and inflammation via inhibition of NF-kappa B activation. These results suggest that cynaroside may be a potential therapeutic agent for the alleviation of periodontitis.