Bilirubin (BIL) ameliorates intracellular reactive oxygen species (ROS) in CsA-induced nephropathy (CIN). 2′,7′-Dichlorofluorescein diacetate (DCFH-DA) was used to determine the intracellular production of ROS. A: Vehicle (VH), B: CsA, and C: BIL + CsA groups (magnification × 400). D: The number of cells with intracellular ROS obtained in at least 10 fields from the A, B and C groups. The data are the means ± SD. *P < 0.05 vs. control, †P < 0.05 vs. CsA.