Abstract:

BACKGROUND: The fully demineralized bone matrix containing bone morphogenetic protein can induce bone marrow-derived mesenchymal stem cells (BMSCs) differentiate into cartilage cells, and keep it characteristics of cartilage cells. It plays an important role in the process of chondrogenesis.
OBJECTIVE: To observe the complexes of BMSCs and fully demineralized bone matrix induced into the cartilage tissue in vitro and to detect the effects on cell apoptosis of culture system and scaffold materials.
METHODS: Porcine BMSCs were isolated with whole bone marrow culture method. The first passage of BMSCs were seeded onto the fully demineralized bone matrix. The BMSCs-fully demineralized bone matrix complex was incubated in inductive medium (high glucose DMEM including transforming growth factor-β1, insulin-like growth factor-Ⅰ, dexamethasone, ascorbic acid and 10% fetal bovine serum) for chondrogenic differentiation, serving as experimental group. The monolayer induced BMSCs, monolayer basic cultured BMSCs and the fully demineralized bone matrix cultured with inductive medium were the control groups. Samples were harvested at week 1, 2, 3 and 4 after culture respectively to observe general morphology. Collagen type Ⅰ, Ⅱ and Aggrecan could be observed by reverse-transcription polymerase chain reaction. The cell apoptosis was detected at 4 weeks.  
RESULTS AND CONCLUSION: The continuous expression of collagen type Ⅰ, and the increased expression of collagen type Ⅱ and Aggrecan could be detected in experimental group and monolayer induced BMSCs group. But the expression in experimental group was higher than that of monolayer induced BMSCs group. The apoptosis of experimental group was higher than monolayer induced BMSCs and monolayer basic cultured BMSCs. The complex of porcine BMSCs and fully demineralized bone matrix could be induced to express cartilage matrix in vitro with transforming growth factor-β1 and insulin-like growth factor-Ⅰ. The expression of extracellular matrix in three-dimensional culture was much higher than that in the monolayer; the static culture systems may influence the apoptosis of BMSCs cultured in three-dimensional environment.