Abstract:

BACKGROUND: The preliminary study confirmed that transfection of insulin-like growth factor-1 (IGF-1) gene can significantly promote the proliferation of adipose-derived mesenchymal stem cells (ADSCs) in two-dimensional culture conditions.
OBJECTIVE: On the basis of preliminary study, to investigate the proliferation capacity of rabbit ADSCs transfected with IGF-1 gene in three-dimensional culture conditions using chitosan gelatin complex scaffold as carrier, and to construct tissue-engineered cartilage initiatively.
METHODS: ADSCs were harvested from the posterior subcutaneous adipose tissue of adult New Zealand white rabbits. After being transfected with pcDNA3.1-IGF-1, the cells were seeded onto Chitosan-gelatin scaffolds, and divided into groups: Blank control group, non-transfected ADSCs was incubated; Empty vector group: ADSCs induced by IGF-1 was incubated; Gene transfection group was transfected ADSCs/scaffold composite. After culture for 1 week, cell morphology was observed by scanning electron microscope (SEM), and the growth curve was measured by MTT, the proliferation and distribution of cells were labeled by CM-DiL, and the contents of glycosaminoglycan in each group were determined by using dimethylmethylene blue dye-binding assay. 
RESULTS AND CONCLUSION: The stable expression of pcDNA3.1-IGF-1 cell lines were established successfully and showed stable expression of IGF-I in mRNA and protein level. SEM showed that the cells exhibited a good attachment and stretch in the scaffold, in which gene transfection group grew the most vigorously. MTT and GAG results suggested that gene transfection group displayed strongest proliferate ability with highest glycosaminoglycan content (P < 0.01). CM-DiL fluorescence showed that the cells distributed  well with the highest survival rate (P < 0.05). Those revealed that transfected rabbit ADSCs with IGF-1 gene can promote the proliferation of ADSCs/scaffold composite and the secretion of chondral extracellular matrix such as glycosaminoglycan.