Artesunate Attenuates Interleukin-1β-Induced the Apoptosis of Chondrocytes, Oxidative Stress Injury and Inflammatory Response: Evidence of the Presence of the Wnt/β-Catenin Pathway

Abstract

Background: Recently, research has borne out that artesunate (ART), an anti-malaria agent, possesses anti-osteoarthritis function, but the mechanisms whereby ART protects the progression of osteoarthritis (OA) remains to be explored. Hence, the current study was aimed at assessing the potential mechanisms of ART in protecting aginst interleukin-1β (IL-1β) -induced rat primary chondrocytes injuries, focusing on the wingless/integrated (Wnt)/β-catenin pathway. Methods: Rat primary chondrocytes isolated from SD rats (4-week-old) were treated with IL-1β to establish an OA model in vitro. Cell viability, lactate dehydrogenase (LDH) release and intracellular reactive oxygen species (ROS) generation, lipid peroxide (malondialdehyde (MDA)) content, and antioxidant enzyme (superoxide dismutase (SOD)) activity were assessed by commercial kits. Cell apoptosis was detected by flow cytometry. The protein expression were determined by western blotting. The inflammatory factors levels were measured by enzyme-linked immunosorbent assay (ELISA). Results: ART significantly increased cell viability, decreased LDH release, and lowered apoptosis comprising apoptosis rate, caspase-3 activity and anti-apoptotic protein (Bax)/pro-apoptotic protein (Bcl-2) ratio in IL-1β-treated rat primary chondrocytes. Additionally, ART suppressed Wnt3a/β-catenin pathway by decreasing Wnt3a/β-catenin, cyclin D1, and c-Myc expressions in IL-1β-exposed rat primary chondrocytes. Furthermore, LiCl, an activator of the Wnt3a/β-catenin pathway, remarkably blocked the beneficial effects of ART during IL-1β injury. In addition, ART attenuated IL-1β-stimulated oxidative stress by reducing ROS generation and MDA content and increasing antioxidant enzyme SOD activity, while these functions of ART were blocked by LiCl. Also, LiCl reversed the anti-inflammatory activity of ART during IL-1β stimulation as illustrated by the increased in nitric oxide level and pro-inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) secretion in rat primary chondrocytes. Conclusions: These findings demonstrated that ART attenuates apoptosis, oxidative stress and inflammation through suppressing the Wnt3a/β-catenin pathway in IL-1β-treated chondrocytes.