Engineered artificial articular cartilage made of decellularized extracellular matrix by mechanical and IGF-1 stimulation

Cartilage engineering has the potential to overcome clinical deficiency in joint disorders. Decellularized extracellular matrix (dECM) has great biocompatibility and bioactivity and can be considered an appropriate natural scaffold for tissue engineering applications. Both insulin-like growth factor-1 (IGF-1) and mechanical compression stimulate the production of cartilage ECM, modulate mechanical properties, and gene expression. The current investigation aimed to fabricate a high-quality moldable artificial cartilage by exposing the chondrocytes in biomimicry conditions using cartilage dECM, IGF-1, and mechanical stimulations. In this study, an ad hoc bioreactor was designed to apply dynamic mechanical stimuli (10 % strain, 1 Hz) on chondrocyte-laden cartilage dECM-constructs with/without IGF-1 supplementation for 2 weeks, 3 h/day. Our data revealed that mechanical stimulation had no adverse effect on cell viability and proliferation. However, it elevated the expression of chondrogenic markers such as collagen type II (COL2A1), aggrecan (ACAN), and proteoglycan-4 (PRG-4), and reduced the expression of matrix metalloproteinase-3 (MMP-3). Mechanical stimulation also promoted higher newly formed glycosaminoglycan (GAG) and produced more aligned fibers that can be responsible for higher Young's modulus of the engineered construct. Even though IGF-1 demonstrated some extent of improvement in developing neocartilage, it was not as effective as mechanical stimulation. Neither IGF-1 nor compression elevated the collagen type I expression. Compression and IGF-1 showed a synergistic impact on boosting the level of COL2A1 but not the other factors. In conclusion, mechanical stimulation on moldable cartilage dECM can be considered a good technique to fabricate artificial cartilage with higher functionality.