euscaphic-acid and Osteoarthritis

Interleukin-1β (IL-1β) accelerates degradation of the cartilage matrix and induces apoptosis of chondrocytes. Tormentic acid (TA) is a triterpene isolated from the stem bark of the Vochysia divergens plant, which has been demonstrated to exert in vitro inhibitory activity against hepatocyte apoptosis. However, the effects of TA on IL‑1β‑induced apoptosis of human chondrocytes remain unclear. Therefore, the present study investigated the in vitro effects of TA on human osteoarthritic chondrocyte apoptosis cultivated in the presence of IL‑1β. Human chondrocytes were pretreated with or without various concentrations of TA and then co‑incubated in the absence or presence of IL‑1β for 24 h. Cell viability was determined using the MTT assay, and cell apoptosis was detected using a Nucleosome ELISA kit. Caspase‑3 activity was detected using a caspase‑3 colorimetric assay kit. The levels of B‑cell lymphoma 2 (Bcl‑2)‑associated X protein (Bax), Bcl‑2, phosphorylated (p)‑phosphoinositide 3‑kinase (PI3K), PI3K, p‑protein kinase B (Akt) and Akt were measured by western blotting. The results revealed that pretreatment with TA inhibited IL‑1β‑induced cytotoxicity and apoptosis in chondrocytes. In addition, TA pretreatment increased B‑cell lymphoma (Bcl)‑2 expression, and decreased caspase‑3 activity and Bax expressionin human chondrocytes. In addition, pretreatment with TA markedly increased the expression of p‑PI3K and p‑Akt in IL‑1β‑induced chondrocytes. Collectively, these results indicate that TA inhibits IL‑1β‑induced chondrocyte apoptosis by activating the PI3K/Akt signaling pathway. Therefore, TA may be considered a potential therapeutic target for the treatment of osteoarthritis.

Topics: Apoptosis; bcl-2-Associated X Protein; Cartilage, Articular; Cell Survival; Cells, Cultured; Chondrocytes; Humans; Interleukin-1beta; Osteoarthritis; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Signal Transduction; Triterpenes

The pro-inflammatory cytokine interleukin-1beta (IL-1β) plays critical roles in pathogenesis of osteoarthritis (OA). Tormentic acid (TA), a triterpene isolated from Rosa rugosa, has anti-inflammatory activity. However, the anti-inflammatory effect of TA on OA is still unclear. So, in the present study, we examined the effect of TA on IL-1β-induced inflammatory response in primary human OA chondrocytes. Our results demonstrated that TA significantly decreased the IL-1β-stimulated expression of matrix metalloproteinase-3 (MMP-3) and MMP-13. It also inhibited the IL-1β-induced expression of inducible nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2), as well as the production of NO and prostaglandin E2 (PGE2) in human OA chondrocytes. Furthermore, TA greatly inhibited the IL-1β-induced NF-κB activation. In conclusion, this study is the first to demonstrate the anti-inflammatory activity of TA in human OA chondrocytes. TA significantly inhibits the IL-1β-induced inflammatory response by suppressing the NF-κB signaling pathway. Thus, TA may be a potential agent in the treatment of OA.

Topics: Anti-Inflammatory Agents; Cells, Cultured; Chondrocytes; Humans; Inflammation; Interleukin-18; NF-kappa B; Osteoarthritis; Signal Transduction; Triterpenes