Engeletin Protects Against TNF-α-Induced Apoptosis and Reactive Oxygen Species Generation in Chondrocytes and Alleviates Osteoarthritis in vivo

Abstract

Purpose Osteoarthritis (OA) is a progressive disease characterized by pain and impaired joint functions. Engeletin is a natural compound with anti-inflammatory and antioxidant effects on other diseases, but the effect of engeletin on OA has not been evaluated. This study aimed to elucidate the protective effect of engeletin on cartilage and the underlying mechanisms. Methods Chondrocytes were isolated from rat knee cartilage, and TNF-α was used to simulate OA in vitro. After treatment with engeletin, the expression of extracellular matrix (ECM) components (collagen II and aggrecan) and matrix catabolic enzymes (MMP9 and MMP3) was determined by Western blotting and qPCR. Chondrocyte apoptosis was evaluated using Annexin V-FITC/PI and flow cytometry. Apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) were evaluated by Western blotting. The mitochondrial membrane potential of chondrocytes was measured with JC-1, and intracellular reactive oxygen species (ROS) levels were determined with DCFH-DA. Changes in signaling pathways (Nrf2, NF-κB and MAPK) were evaluated by Western blotting. In vivo, anterior cruciate ligament transection (ACLT) was used to induce the rat OA model, and engeletin was administered intraarticularly. The therapeutic effect of engeletin was analyzed by histopathological analysis. Results Pretreatment with engeletin alleviated TNF-α-induced inhibition of ECM components (collagen II and aggrecan) and upregulation of matrix catabolic enzymes (MMP9 and MMP3). Engeletin ameliorated chondrocyte apoptosis by inhibiting Bax expression and upregulating Bcl-2 expression. Engeletin maintained the mitochondrial membrane potential of chondrocytes and scavenged intracellular ROS by activating the Nrf2 pathway. The NF-κB and MAPK pathways were inhibited by treatment with engeletin. In vivo, ACLT-induced knee OA in rats was alleviated by intraarticular injection of engeletin. Conclusion Engeletin ameliorated OA in vitro and in vivo. It may be a potential therapeutic drug for OA.

Physalin A Inhibits MAPK and NF-κB Signal Transduction Through Integrin αVβ3 and Exerts Chondroprotective Effect

“…IL-1β, a cytokine, was widely used to activate the above two signaling pathways. According to current research, inhibiting the transduction of the above two signaling pathways triggered by IL-1β can alleviate the cartilage destruction in OA ( Wang et al, 2021a ). Thus, we analyzed proteins related to the MAPK and NF-κB pathways to determine the timing of activation of the above two pathways induced by IL-1β at those time points (0, 10, 30, and 60 min).…”

Etomidate ameliorated advanced glycation end-products (AGEs)-induced reduction of extracellular matrix genes expression in chondrocytes

“…Pro-inflammatory cytokines, such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), could activate many inflammatory signaling pathways including nuclear factor – κB (NF-κB) to promote an inflammatory cascade. It is well known that RAGE, a member of the immunoglobulin superfamily, is expressed in human chondrocytes [ 38 ]. When AGEs bind to RAGE, they activate MAP kinase signaling, resulting in upregulation of NF-κB activity, which promotes the inflammatory cascades [ 39 ].…”

Recent Advances in Reactive Oxygen Species (ROS)-Responsive Polyfunctional Nanosystems 3.0 for the Treatment of Osteoarthritis

“…Pretreatment with engeletin alleviated TNF-α-induced inhibition of ECM synthesis (collagen II and aggrecan) and upregulation of matrix catabolic enzymes (MMP9 and MMP3) and scavenged intracellular ROS by activating the Nrf2 pathway. 69 Tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) has excellent antioxidant and anti-inflammatory effects by decreasing superoxide ion levels in LPS-induced macrophages. 70 In addition, resveratrol has a strong protective effect against B[a]P-induced intracellular ROS generation by increasing mitochondrial content and function.…”