Doxorubicin suppresses chondrocyte differentiation by stimulating ROS production

Doxorubicin (DOX) is widely used as an effective chemotherapy agent in human cancer. Our study aimed to explore the specific mechanism of DOX in osteoarthritis (OA).A mouse OA model was established by destabilizing the medial meniscus (DMM), and the role of DOX was determined by intraperitoneally injecting 5 or 10 mg/kg DOX. The expression of collagen type-II (Col-2) was detected by immunohistochemistry staining, and the expression of plasma interleukin (IL)-6 (IL-6), IL-1beta (IL-1β), and tumor necrosis factor (TNF)-alpha (TNF-α) was evaluated by specific ELISA kits, and the expression of Sry-related HMG box 9 (SOX-9) was detected by western blot. Bone marrow mesenchymal stem cells (BMMSCs) were used to explore the mechanism of DOX in vitro. Reactive oxygen species (ROS) production was determined by flow cytometry. Cell viability was measured by Cell Counting Kit-8 (CCK-8) assay. Chondrocyte differentiation was evaluated by Alcian blue staining assay. The expression of chondrocyte differentiation-related markers was detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR).DOX exposure exacerbated OA progression and inhibited chondrocyte differentiation of BMMSCs. DOX also increased ROS production in BMMSCs. Meanwhile, DOX further increased the elevation of plasma IL-6, IL-1β and TNF-α induced by DMM and obviously reduced the expression of chondrocyte differentiation-related markers, including collagen type II a1 (Col2A1), collagen type X alpha 1 (Col10A1), and aggrecan. Moreover, ROS scavengers NAC and MitoQ efficiently alleviated DOX toxicity, including ROS production and chondrocyte differentiation in BMMSCs.Our study revealed that DOX suppressed chondrocyte differentiation by stimulating ROS production, providing a novel theoretical strategy for the clinical treatment of OA caused by DOX.