Bone marrow aspirate concentrate (BMAC) is increasingly recognized as a valuable orthobiologic, offering promising outcomes in reducing inflammation, alleviating pain for patients with osteoarthritis (OA) and various musculoskeletal conditions. However, BMAC contains a very low percentage of mesenchymal stem cells (MSCs), and multiple injections are often required with multiple harvests, which can lead to scarring at the extraction site and patient discomfort. This study aimed to determine whether freezing BMAC affects the function of MSCs in vitro and their capacity to repair articular cartilage in vivo using an OA rat model. BMAC was obtained from patients undergoing BMAC treatment. The in vitro results showed that the proliferation and multilineage differentiation of MSCs remained similar after being frozen for 4 weeks at -80 °C. In vivo, both fresh and frozen BMAC demonstrated significantly improved ICRS histology score of tibial plateau cartilage compared to the PBS control. No significant difference was found between fresh and frozen BMAC treatment groups. Our results suggest that the freezing process does not negatively affect the function of MSCs from BMAC for cartilage repair. These findings support the potential future applications of a single harvest with BMAC storage for multiple injections, thereby enhancing the tissue repair capabilities of BMAC.
Keywords: cartilage repair; chondrogenic differentiation; fresh and frozen bone marrow aspirate concentrate (BMAC); mesenchymal stem cell (MSC); osteoarthritis (OA).