Objective: This study aims to investigate the difference of proliferation patterns and osteogenic and adipogenic differentiation capability of adipose-derived stromal cells (ADSCs) obtained from human lipoaspirates, rat and rabbit inguinal subcutaneous adipose tissues in vitro.
Methods: Adipose tissues of healthy adults were obtained by liposuction. Human ADSCs were isolated from these adipose tissues and cultured in DMEM containing 10% fetal bovine serum (FBS). Rat and rabbit ADSCs were obtained from inguinal subcutaneous adipose tissues and cultured with the same methods. These cells were observed under inverted microscope each day and cell growth was measured with MTT assay. Adipogenic differentiation was induced by culturing ADSCs for 1 or 2 weeks in adipogenic medium (AM) containing 1 micromol/L dexamethasone, 10 micromol/L insulin, 200 micromol/L indomethacin, 0.5 mmol/L isobutyl-methylxanthine (IBMX), and assessed by Oil Red O staining as an indicator of intracellular lipid accumulation. Osteogenic differentiation was induced by culturing ADSCs in osteogenic medium (OM) containing 0.1 micromol/L dexamethasone, 50 micromol/L ascorbate-2-phosphate, 10 mmol/L beta-glycerophosphate, and examined via alkaline phosphatase (AP) activity and extracellular matrix (ECM) calcification by alizarin red S staining and quantification of matrix calcification.
Results: Fibroblast-like cells were digested from both inguinal subcutaneous adipose tissues of rabbit or rat and human lipoaspirates obtained from subcutaneous adipose tissues. Lipid-filled droplets were accumulated in human, rat and rabbit ADSCs upon treatment with adipogenic medium and were stained by Oil Red O. No lipid droplets were observed in the control undifferentiated ADSCs. After exposure to osteogenic differentiation medium, human and rat ADSCs were found to possess greater osteogenic potentials than cells isolated from rabbit inguinal subcutaneous adipose tissues, which was evidenced by significantly different osteogenic markers including alkaline phosphatase and mineral deposition.
Conclusion: Rabbit ADSCs obtained from inguinal subcutaneous adipose tissues poorly possess osteogenic potentials compared with ADSCs of human lipoaspirates obtained from subcutaneous adipose tissues or ADSCs of rat from inguinal subcutaneous adipose tissues, although they all possess comparable adipogenic capacity.