Characterization and enhancement of chondrogenesis in porous hyaluronic acid-modified scaffolds made of PLGA(75/25) blended with PEI-grafted PLGA(50/50)

Hyaluronic acid (HA) improves the quality of microfracture-mediated cartilage regeneration by recruiting bone marrow mesenchymal stem cells (BMSCs) and chondrocytes. An HA-enriched scaffold was investigated to enhance chondrogenesis by BMSCs and chondrocytes in articular cartilage tissue engineering with the microfracture technique. Pre-fabricated porous PGP2/1 [poly(d,l-lactic acid-co-glycolic acid)(75/25) blended with polyethylenimine-grafted-poly(d,l-lactic acid-co-glycolic acid)(50/50) in a 2:1 ratio] scaffolds with 72.7% porosity and a 200–400-μm pore size were generated via the gas foaming/salt leaching method. HA-modified porous PGP2/1 (HA-PGP) scaffolds were used as the HA-enriched microenvironment. The mRNA levels of chondrogenic marker genes (SOX-9, aggrecan and type II collagen) were quantified using real-time polymerase chain reaction (PCR). Sulfated glycosaminoglycan (sGAG) deposition was detected by Alcian blue staining and dimethylmethylene blue (DMMB) assays. The expression of the chondrogenic genes type II collagen and aggrecan was significantly elevated in chondrocytes and BMSCs grown on HA-PGP scaffolds after seven days of culturing. BMSCs cultured in HA-PGP scaffolds showed increased sGAG content after four weeks of culturing. These results demonstrate that HA-PGP scaffolds provide a microenvironment that induces chondrogenesis by chondrocytes and BMSCs, which may be beneficial for regenerating cartilage-like tissue in vivo with the microfracture technique.