BACKGROUND:Our previous studies have shown that a soft substrate has a significant effect on morphology and cytoskeleton of rat bone marrow mesenchymal stem cel.
OBJECTIVE:To explore the effect of polyacrylamide gels as soft substrates with different elastic moduli on the chondrogenic differentiation of human synovial-derived mesenchymal stem cels.
METHODS:The synovium was harvested from patients with osteoarthritis under sterile conditions, and primary human synovial-derived mesenchymal stem cels were separated using limiting dilution assay. The flow cytometry and multi-directional differentiation experiments were used to identify the cel surface markers and function of the human synovial-derived mesenchymal stem cels, respectively. The polyacrylamide gels with the elastic modulus of 0.4, 6, 30 kPa, which were made using various amounts of acrylamide and bis-acrylamide, were used to culture human synovial-derived mesenchymal stem cels under induction with transforming growth factor-β1 for 7 and 14 days. RT-PCR was used to test the expression of chondrogenic genes, type II colagen gene and cartilage acidic protein 1. The 6-wel cel culture plates served as controls.
RESULTS AND CONCLUSION: The human synovial-derived mesenchymal stem cels showed different cel morphology in the different elastic modulus of polyacrylamide gels. The expression of type II colagen gene and cartilage acidic protein 1 were affected by the different elastic modulus of polyacrylamide gels and culture time, and there was an interaction between these two factors. At 7 days of induction, the expression of cartilage acidic protein 1 gene on 6 kPa polyacrylamide gels was the highest (F=44.350,P=0.000); meanwhile, the expression of type II colagen gene on 0.4 kPa polyacrylamide gels was the highest (F=6.384,P=0.005). These findings indicate that polyacrylamide gels with lower elastic modulus are superior to routine culture plates to promote the chondrogenic differentiation of human synovial-derived mesenchymal stem cels.