LAUSR

Background & Aim The placenta-derived mesenchymal stem cells have great interest as a promising cell source for regenerative medicine due to non-invasive collection, readily availability, high expansion capacity, and low immunogenicity. We investigated the feasibility of transplanting placenta-derived MSCs and a hyaluronic acid (HA) hydrogel composite to repair full-thickness articular cartilage defects and determine whether the transplantation of various concentrations of placenta-derived MSCs with 4% hyaluronic acid (HA) hydrogel promoted articular cartilage repair in a rabbit model. Methods, Results & Conclusion Methods Critical-sized osteochondral defects (5mm diameter × 5mm depth) were created in the center of the trochlear groove of femur. The Four experimental groups were as follows: group A, defect only (left knee)/ 4% HA hydrogel without placenta-MSCs (right knee), n=6; group B, 0.01 × 107 cells/ml with 4% HA hydrogel (left knee)/ 0.1 × 107 cells/ml with 4% HA hydrogel (right knee), n=8; group C, 0.1 × 107 cells/ml with 4% HA hydrogel (left knee)/ 0.5 × 107 cells/ml with 4% HA hydrogel (right knee), n=8; group D, 0.5 × 107 cells/ml with 4% HA hydrogel (left knee)/ 1 × 107 cells/ml with 4% HA hydrogel (right knee) were transplantation in a rabbit model. At 8 weeks after transplantation, the degree of cartilage repair was evaluated grossly and histologically using the International Cartilage Repair Society macroscopic score, the modified O'Driscoll score for histologic grading. Results Transplanting placenta-derived MSCs and a HA hydrogel composite resulted in overall superior cartilage repair tissue with better quality than no treatment and hyaluronic acid (HA) only treatment group. Interestingly, The 0.5 × 106 cells/ml group showed the highest cartilage repair at 8 weeks post transplantation. Conclusions The results of this study suggest that transplantation of the composite of placenta-derived MSCs and HA is promoting for cartilage repair. In addition, this study shows that optimal MSC concentration needs to be determined for better cartilage repair.