Resveratrol inhibits collagen I synthesis by suppressing IGF-1R activation in intestinal fibroblasts

Figure 2 Insulin growth factor-1 induces collagen I expression via mitogen-activated protein-kinase pathway. A, B: Collagen I protein and col1a2, col1a1 mRNA expression in mouse intestinal fibroblasts (MIFs) and CCD-¹⁸Co cells stimulated with increasing concentrations of insulin growth factor-1 (IGF-1) for 24 h; C: Phosphorylation of IGF-1 receptor (IGF-1R) (p-IGF-1R) and extracellular signal-regulated kinase 1/2 (ERK1/2) (p-ERK1/2) in MIFs and CCD-¹⁸Co exposed to 100 ng/mL IGF-1 for 0, 15, 30, or 60 min. The bar graph represents the quantitation of the Western blotting normalized to the control; D: Cells were pretreated with 50 μmol/L mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK)/ERK inhibitor U0126 or vehicle for 1 h and then coincubated with 100 ng/mL IGF-1 for 24 h. Collagen I protein level was measured. The experiment was repeated three times and obtained similar results. Values represent mean ± SD. ^bP < 0.01 vs no treatment group. GAPDH: Glyceraldehyde 3-phosphate dehydrogenase.