Figure 2. Effect of Zn²⁺ on Cd²⁺-induced accumulation of reactive oxygen species (ROS) in MDBK cells.

(A) MDBK cells were treated with 10 μM CdCl₂, alone or in combination with ZnCl₂ (0, 10, or 50 μM), for 6 h. Intracellular ROS accumulation was assessed by DCFH-DA staining and imaged using a fluorescence microscope at ×200 magnification. (B) Cells were treated with Zn²⁺ and/or Cd²⁺ as indicated. Intracellular ROS was determined by flow cytometry following staining with DCFH-DA and the percentage of ROS-positive cells was quantified. The data represent the mean ± SD (n = 4). ##P<0.01, and ###P<0.001, compared to the medium-treated control group; *P<0.05 and **P<0.01 compared to the cells exposed to Cd²⁺ alone (10 or 50 μM).