Menstrual Blood-Derived Mesenchymal Stem Cell Paracrine Factors Stimulate Chondrogenesis in vitro and Possess Protective Effects to Articular Cartilage

Abstract Background Articular cartilage is an avascular tissue with limited capacity to self-regeneration, which leads to challenges treating injuries or diseases such as osteoarthritis (OA). Mesenchymal stem cells (MSCs) are a promising tool for cartilage tissue engineering, as they are capable to differentiate into chondrogenic lineage cells and secrete a number of active molecules important for stimulating chondrocyte anabolic pathways and modulate the metabolism of cartilage extracellular matrix (ECM). Bone marrow-derived MSCs (BMMSCs) are the most widely used for development of cartilage tissue regeneration technologies, however, other sources of stem cells, like menstrual blood, may have advantages due to the ease of access. The aim of this study was to evaluate the potential of menstrual blood-derived MSC (MenSC) paracrine factors in stimulating BMMSCs chondrogenic differentiation and to investigate their role in protecting cartilage from degradation under inflammatory conditions in vitro.Methods In this study, we induced MenSCs and BMMSCs chondrogenic differentiation, using four different growth factors, important for stimulation of chondrogenesis in MSCs – transforming growth factor β-3 (TGF-β3), activin A, bone morphogenetic protein 2 (BMP-2) and insulin growth factor 1 (IGF-1). We stimulated chondrogenic differentiation in BMMSCs co-cultured with MenSCs or cartilage explants co-cultured with MenSCs for 21 days under inflammatory conditions. After, we evaluated chondrogenic capacity of BMMSCs in co-cultures by immunohistochemical staining, secretion of four growth factors and cartilage oligomeric matrix protein, as well as measured release and synthesis of cartilage extracellular matrix proteins and gene expression in cartilage explants after co-culturing them with MenSCs.Results Our results suggest that MenSCs stimulate chondrogenic response in BMMSCs by secreting activin A and TGF-β3, and may have protective effects on cartilage tissue ECM by decreasing release of GAGs into medium, most likely through modulation of activin A related molecular pathway.Conclusion In conclusion, paracrine factors secreted by MenSCs may turn out to be a promising therapeutical approach for cartilage tissue protection and repair.