[Effects of insulin on the growth factor secreting function of adipose-derived stem cells]

To study the effect of insulin in different concentrations on secretion function of growth factors of adipose-derived stem cells (ADSCs).

ADSCs were isolated from human abdominal adipose tissue and cultured. The immunophenotype and adipose induced-differentiation were identified, and the third generation cells were collected. The collected cells were assigned to 1 x 10(-8), 1 x 10(-7), 1 x 10(-6) mol/L insulin groups according to the concentration of added insulin. When cells grew into 70% confluence in conventional medium, ADSCs were cultured further in serum-free DMEM containing insulin in different concentrations for 3 days. ADSCs cultured in medium without insulin were used as control group. Secretion amount of vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) of ADSCs were determined by enzyme-linked immunosorbent assay. The effects of the supernatant fluid of ADSCs' nutrient solution on the proliferation and collagen synthesis of the cultured fibroblast were detected by MTT chromatometry and hydroxyproline chromatometry.

The secretion amounts of VEGF and HGF of ADSCs in 1 x 10(-8) and 1 x 10(-7) mol/L insulin groups [(471 +/- 41, 762 +/- 66 ng/L), (643 +/- 64, 930 +/- 67 ng/L), respectively] were significantly higher as compared with those in control group (286 +/- 47, 577 +/- 84 ng/L) (P < 0.05 or P < 0.01). No change occurred in the secretion amount of VEGF and HGF of ADSCs in 1 x l0(-6) mol/L insulin group (P > 0.05). The supernatant fluid of ADSCs' nutrient medium of 1 x 10(-8), 1 x 10(-7) mol/L insulin groups showed obvious stimulative effect on the proliferation and collagen synthesis of fibroblasts, and it was most obvious in the 1 x 10(-7) mol/L group (P < 0.05 or P < 0.01).

Insulin in the concentrations of 1 x 10(-8) and 1 x 10(-7) mol/L can notably promote ADSCs' function of secreting VEGF and HGF.