Wogonin pretreatment of infrapatellar fat pad mesenchymal stem cell-derived exosomes advances articular cartilage repair in osteoarthritis

Aims Osteoarthritis (OA) is a chronic joint disorder characterized by progressive cartilage degeneration, inflammation, and subchondral bone remodelling. Herein, the role of exosomes (Exos) extracted from wogonin-pretreated infrapatellar fat pad mesenchymal stem cells (MSCs IPFP ) was explored, and their ability to promote cartilage defect repair in OA was clarified. Methods In this study, the therapeutic effects of wogonin on MSCs IPFP -derived Exos and OA chondrocytes were investigated in vitro, and a mouse OA model was studied in vivo. Human-derived chondrocytes and MSCs IPFP were isolated and cultured. These cells were characterized through morphological observation, toluidine blue staining, immunofluorescence staining, detection of stem cell surface markers, and induction of directed differentiation. DiI dye was used to label and trace MSCs IPFP -derived Exo (MSCs IPFP -Exo). Chondrocyte inflammation and the mouse OA model were induced using interleukin (IL)-1β and destabilization of the medial meniscus (DMM) surgery. To evaluate chondrocyte proliferation and apoptosis, cell counting kit (CCK)-8 assay and flow cytometry were conducted. Articular cartilage destruction in mice was assessed using haematoxylin and eosin (H&E) staining, Safranin O/Fast Green staining, and the Osteoarthritis Research Society International (OARSI) score. Additionally, immunohistochemical staining and/or western blot were performed to examine the expression of Sox9, aggrecan, type II collagen (collagen II), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), and matrix metalloproteinase 13 (MMP13). Results The isolated chondrocytes could uptake MSC IPFP -Exo. Wogonin-MSC IPFP -Exo enhanced chondrocyte proliferation and suppressed apoptosis; Wogonin-MSC IPFP -Exo significantly alleviated cartilage tissue damage in OA mice compared to untreated controls and MSC IPFP -Exo-treated OA mice in in vivo experiments. Mechanistically, wogonin-MSC IPFP -Exo upregulated Sox9, aggrecan, and collagen II protein levels, while downregulating ADAMTS5 and MMP13 protein levels compared to untreated controls and MSC IPFP -Exo-treated OA mice. Conclusion Wogonin pretreatment significantly enhances the ability of MSC IPFP -Exo to promote cartilage defect repair, and it is expected to be a promising agent for the clinical treatment of OA. Further preclinical and clinical studies are necessary to validate the safety, efficacy, and long-term outcomes of this therapeutic approach before its translation into clinical practice for the treatment of OA. Cite this article: Bone Joint Res 2025;14(12):1064–1079.