Figure 5. Expression of Smad increased in C2C12 cells treated with indoxyl sulfate. SMAD Luciferase reporter assays demonstrated the indoxyl sulfate increased the SMAD expression at concentration of 250 uM (p < 0.05). The treatment of resveratrol (10 uM) decreased the expression of Smad in C2C12 cells co-treated with indoxyl sulfate. *p < 0.05, when comparing to the C2C12 cells treated with lentiviral reporting assay. Abbreviations: IS: indoxyl sulfate; pLVX-Puro: plasmid lentiviral expression vector; pLVX-Puro-SBE-Luciferase: plasmid lentiviral expression vector with Smad binding element luciferase; RSV: resveratrol.