Abstract:

BACKGROUND: Recently, researches have found that insulin-like growth factor-1 (IGF-1) can induce the differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) into chondrocytes, but there are no reports concerning the differentiation of adipose-derived mesenchymal stem cells (ADMSCs) into chondrocytes induced by IGF-1, as well as interaction with transforming growth factor-β1 (TGF-β1) during this process. 

OBJECTIVE: To explore the possibility of inducing ADMSCs chondrogenic differentiation by using IGF-1 and the interaction with TGF-β1 in induction.

METHODS: ADMSCs were obtained, and seeded at 2×10⁵cells/cm² in culture flask. Insulin-free chondrogenic media containing IGF-1 or (and) TGF-β1 were used to induce ADMSCs. 2 weeks later, cells were harvested and stained by using toluidine blue and collagen Ⅱ antibody immunohistochemistry. Intracellular sulfated proteoglycan and collagen Ⅱ coloring were observed. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of collagen Ⅱ, aggrecan and Sox9 mRNA.

RESULTS AND CONCLUSION: After induced, toluidine blue stain exhibited that the cells in the three induction groups were polygonal, with cytoplasm and cell membrane of blue different dyeing. Immunohistochemistry for type II collagen demonstrated that cytoplasm and cell membrane were stained brown in three induction groups. RT-PCR revealed that the expression of collagen Ⅱ, aggrecan, Sox9 mRNA of IGF + TGF group were significantly greater than the IGF and TGF groups, and IGF and TGF groups were significantly stronger than the control group. No significant difference was determined between the IGF and TGF groups. These results indicated that IGF-1 can induce chondrogenic differentiation from ADMSCs, expressing chondrocyte specific cell phenotype. There is synergism of IGF-1 and TGF-β1 to induce the differentiation of ADMSCs into chondrocytes.