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

Figure 3 Resveratrol inhibits insulin growth factor-1-induced collagen I expression partly through silent information regulator 1. A, B: Collagen I protein and col1a2 mRNA expression were measured in fibroblasts stimulated with insulin growth factor-1 (IGF-1) (100 ng/mL) or IGF-1 plus resveratrol (RSV 50, 100 μmol/L) for 24 h; C: Wild type silent information regulator 1 (SIRT1) (WT) or enzyme deficient SIRT1 (HY) constructs were transfected into CCD-¹⁸Co cells followed by treatment with IGF-1. Collagen I protein was measured by Western blotting; D: Cells were transfected with the empty vector (pcDNA3.0) or SIRT1 WT, then collagen I, SIRT1, phosphorylation of extracellular signal-regulated kinase (ERK) (p-ERK) or total ERK1/2 (t-ERK1/2) were examined by Western blotting; E: 293T cells were transiently transfected with SIRT1-specific small interfering RNAs (siRNAs) (1, 2, 3) or scrambled siRNA (SCR) for 48 h, then SIRT1 protein and mRNA expression was measured by Western blotting and quantitative real-time polymerase chain reaction; F: CCD-¹⁸Co cells were transfected with SIRT1 siRNAs (1, 3) or SCR followed by treatment with resveratrol. The collagen I/glyceraldehyde 3-phosphate dehydrogenase (GAPDH) ratio shows the quantification of the expression levels of collagen I (Relative Amount). The experiment was repeated three times and obtained similar results. Values represent mean ± SD. ^aP < 0.05, ^bP < 0.01 vs control.