Metformin attenuates motility, contraction, and fibrogenic response of hepatic stellate cells in vivo and in vitro by activating AMP-activated protein kinase

Figure 5 Effect of metformin on VEGF expression and secretion of hepatic stellate cells and angiogenesis in vitro. A and B: HSCs were incubated with or without PDGF-BB (10 ng/mL) for 24 h or CoCl₂ (150 μmol/L) for 12 h and metformin (1, 2, 5, and 10 mmol/L). The expression levels of HIF-1α and VEGF were measured by Western blot analysis, and the results were quantified; C: Cells were treated as in panel B, and the supernatant was collected. The protein level of VEGF was measured by ELISA assay; D and E: HSCs were pretreated with metformin (5 and 10 mmol/L) or AICAR (500 μmol/L) for 2 h, and then incubated with or without CoCl₂ (150 μmol/L) for 12 h. The supernatant was collected and diluted 4:1 (v/v) in DMEM with 10% FBS to form conditioned medium. HUVECs were harvested and suspended in the conditioned medium, and then seeded on Matrigel. Images were acquired at 8 h (100 × magnification), and tube lengths were calculated with ImageJ and quantified. ^aP < 0.05 and ^bP < 0.01 vs the control group, ^cP < 0.05 and ^dP < 0.01 vs the PDGF-BB or CoCl₂ only groups. HSCs: Hepatic stellate cells.