The Enhancing Effect of Mechanical Stimulation on the Chondrogenic Function of Infrapatellar Fat Pad Stem Cells

The infrapatellar fat pad (IPFP), a specialized fibrofatty structure within the anterior compartment of the knee joint, is characterized by a unique microarchitecture featuring interspersed collagen bundles and adipose lobules, which collectively establish its viscoelastic biomechanical properties. Emerging evidence highlights the distinctive transcriptional profile of IPFP-SCs, specifically their association with cartilage degradation mediators during osteoarthritis progression. Recent research demonstrates that dynamic compression and hydrostatic pressure effectively enhance chondrogenic differentiation of both bone marrow-derived and IPFP-derived mesenchymal stem cells while inhibiting calcification deposition. This study utilized a cell stretching system to simulate the cyclic mechanical stress environment of the knee joint, demonstrating that dynamic tensile stimulation (10% strain, 1 Hz) significantly enhances the chondrogenic differentiation capacity of IPFP-SCs. This enhancement was manifested by upregulated expression of chondrogenic markers, including SOX9 and COMP, confirming that the joint-specific mechanical microenvironment plays a critical regulatory role in the terminal differentiation of mesenchymal stem cells. These results provide crucial experimental evidence for cartilage tissue regeneration strategies, emphasizing the importance of biomechanical modulation in regenerative therapies for cartilage repair.