Experimental study on co-culturing adipose-derived stem cells with osteoblasts under different conditions.

OBJECTIVE: To observe whether adipose-derived stem cells (ADSCS), co-cultured with osteoblasts, can differentiate into osteoblasts and, if so, to study the best-induced conditions, with an ultimate goal of repairing bone defects. MATERIALS AND METHODS: Adipose-derived stem cells and osteoblasts were isolated from New Zealand white rabbits, and co-cultured in media with either 5% or 10% fetal bovine serum, for up to 4 weeks. The morphology of collected cells was examined under a microscope, and histological staining with alkaline phosphatase and alizarin red was carried out after induction for 1, 2, 3 and 4 weeks. Osteogenesis identification, including mRNA expression of type I collagen and osteocalcin, and alkaline phosphatase, was also performed using RT-PCR. RESULTS: After 7 days of co-culture, some adipose-derived stem cells became round in both groups. After 14 days of co-culture, adipose-derived stem cells were found highly-differentiated, and stained positively with alkaline phosphatase and alizarin red, similar to mature osteoblasts. The mRNA expression of type I collagen and osteocalcin increased in both groups, especially in the 10% fetal bovine serum group. CONCLUSIONS: Our findings indicate that adipose-derived stem cells co-cultured with osteoblasts can differentiate into osteoblasts when induced by a high concentration of serum culture.