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BACKGROUND: With the development of tissue engineering technology, the use of natural biological materials as scaffolds can accelerate the formation of new cartilage tissue and facilitate the repair of cartilage defects. OBJECTIVE: To explore the ability of cartilage extracellular matrix-derived particles to repair cartilage defects in the weight-bearing area. METHODS: Extracellular matrix-derived particles were prepared by decellularization of goat knee cartilage. Twelve Chinese goats (provided by the Experimental Animal Center of PLA General Hospital in China) were selected to make a full-thickness osteochondral defect model with a diameter of 8 mm and a depth of 2 mm in the weight-bearing area of the inner and outer condyles of the right femur. These goat models were randomly divided into two groups. In the experimental group (n=6), the cartilage extracellular matrix-derived particles were implanted to the defect and fixed with fibrin glue. The control group (n=6) was only filled with fibrin glue. General, histological and biomechanical evaluations were conducted with distal right femur samples taken at 3 and 6 months after implantation. RESULTS AND CONCLUSION: (1) Hematoxylin-eosin staining: The defect was basically not repaired at 3 months after implantation in the control group, with a small amount of fibrous tissue filling, sag in the defect area, matrix staining and poor integration of the bilateral interface; at 6 months after implantation, the defect area in the control group was still mainly filled with fibrous tissues and contained a small amount of fibrous cartilage, and there was still a clear boundary between the new tissue and surrounding normal tissue. At 3 months after implantation, the defect area of the experimental group was smaller than that of the control group, and the new tissue was a complex of fibrocartilage and hyaline cartilage. At 6 months after implantation, the proportion of tissue hyaline cartilage in the defect area of the experimental group increased, and the surface was relatively smooth, similar to the surrounding normal cartilage tissue, and well integrated. Enlarged cartilage lacunae were visible and the cells are arranged in order. (2) Safranine O-Fast Green staining: At 3 months after implantation, the defect area of the control group was basically free of proteoglycan red stain, while the defect area of the experimental group showed obvious proteoglycan coloring. At 6 months after implantation, the amount of proteoglycan-stained new tissue in the experimental group was significantly higher than that in the control group, and the proportion of hyaline cartilage in the new tissue was higher in the experimental group, similar to that of surrounding normal cartilage. (3) Biomechanical analysis: Six months after implantation, the average Young’s modulus of the experimental group was significantly higher than that of the control group (P < 0.05). All the findings reveal that the use of cartilage extracellular matrix-derived microparticles can promote the repair of cartilage defects. [ABSTRACT FROM AUTHOR]

BACKGROUND: With the development of stem cell therapy and tissue engineering, adipose-derived mesenchymal stem cells combined with biocompatible scaffolds have been introduced to constructing liver tissue engineering micro-units as a new strategy for the treatment of liver diseases. OBJECTIVE: To investigate the repairing ability of adipose-derived mesenchymal stem cells combined with porous chitosan microspheres on acute liver injury. METHODS: Adipose-derived mesenchymal stem cells from neonatal Sprague-Dawley rats and porous chitosan microspheres were co-cultured in vitro to observe the proliferation of adipose-derived mesenchymal stem cells on the microspheres on the 1st, 3rd and 5th days. Thirty-six Sprague-Dawley rats (provided by Beijing Vital River Laboratory Animal Technology Co., Ltd. in China) were randomly divided into three groups (n=12 per group): control group was intraperitoneally injected with normal saline; acute liver injury group was intraperitoneally administered with 10% carbon tetrachloride-olive oil; and cell-microsphere group was intraperitoneally given 10% carbon tetrachloride-olive oil and then adipose-derived mesenchymal stem cells-porous chitosan microspheres were implanted into the liver surface on the 1st day after injection. Gross, serological and histological evaluations were performed on the 1st, 2nd, 3rd and 7th days. RESULTS AND CONCLUSION: Adipose-derived mesenchymal stem cells-porous chitosan microspheres were stained with live/dead staining on the 1st, 3rd and 5th days. The cells grew normally on the microspheres as the number of dead cells was much less than that of living cells, and the cells proliferated continuously over time. The gross score, liver function score and histological score of the cell-microsphere group were higher than those of the acute liver injury group on the 1st, 2nd, 3rd and 7th days. There was no significant difference between the cell-microsphere group and control group since the 3rd day. All these experimental findings indicate that adipose-derived mesenchymal stem cells-porous chitosan microspheres implanted onto the liver surface can accelerate the repair of liver injury. [ABSTRACT FROM AUTHOR]