Experimental Study Of Implantion Of A Scaffold-free Tissue-engineered Construct Generated From Mesenchymal Stem Cells

Objective: At present,stem cell therapy has become a new direction to promote the repair of regenerative tissue.Mesenchymal stem cells(MSCs)are the source of cells,and implantion of a scaffold-free tissue-engineered construct(TEC)generated from MSCs has achieved better therapeutic effects in the repair of cartilage damage.The effect of SFMSCs-TEC transplantation on repairing cartilage defects was evaluated in comparison with injection of MSCs mixed hyaluronic acid(HA)method.Method: Five 6-month-old porcines were used.The cartilage defect model was made in double knee joint femoral trochlear.The left side was the experimental group,The TEC based on the(SFMSCs)was used for repair in this group(SFMSCs-TEC Group).The right side was the control group,and mesenchymal stem cells composite hyaluronic acid(HA)were injected into articular cavity in this group(SFMSCs-HA Group).The two groups were evaluated at three months after surgery,and the general observation,MR imaging examination,HE staining,and toluidine blue staining were performed.Collagen II immunohistochemical staining and general scoring and histological scoring were performed with reference to the International Cartilage Repair Association(ICRS)Cartilage Repair Scoring System.Results: The porcine SFMSCs were used as the cell source,and the scaffold free MSCs-TEC were successfully constructed.The results of the two groups in the postoperative 3 months:(1)Gross observation: The cartilage defect in the experimental group was basically grayish cartilage-like tissue.Most of the surface is flat,and the boundary with normal tissue is blurred.In the control group,obvious depressions were still visible in the cartilage defect site,the gray-white cartilage tissue was thinner,and the surrounding boundary was obvious.All the samples showed obvious synovitis and joint effusion.(2)MR imaging examination: The surface and internal signals of the repaired tissue,the subchondral bone edema signal,and the joint cavity joint fluid signal test group were better than the control group.(3)HE staining,toluidine blue staining and Collagen II immunohistochemical staining showed that some hyaline cartilage was observed in the experimental group,and the boundary between the surrounding normal tissues was blurred,and the extracellular matrix was positively stained.The control group showed fibrocartilage repair and surrounding normal tissues.The boundary was clear and the extracellular matrix was not stained.(4)General score of ICRS: The experimental group and the control group were 9.67±1.04 and 5.75±1.38,9.67±1.04?5.75 ± 1.38.ICRS histological score: experimental group and the control group were9.74 ± 1.9 and 5.43 ± 1.18,respectively.The difference between the two groups was statistically significant(P<0.05).Conclusion: Compared with SFMSCs-HA method,the short-term effect of scaffold free SFMSCs-TEC technique in the treatment of articular cartilage defects in pigs had better repair effect,and can bring more hyaline cartilage repair and reduce arthritis reaction.