Fig. 3.

ATRA has no significant effect on PAP-induced reactive oxygen species (ROS) generation or reduced GSH levels. A: LLC-PK₁ cells were pretreated with ATRA (25 μM 24 h), loaded with CM-H₂DCFDA dye, and exposed to PAP (150 μM, 0–2 h). NAC (10 mM) was cotreated with PAP and used as a positive control. LLC-PK₁ cells were pretreated with ATRA (25 μM, 24 h) followed by treatment with PAP (150 μM) for 1 h (B) or 2 h (C). ■: Control cells; □: cells treated with ATRA; △: cells treated with PAP; ⧫: cells pretreated with ATRA followed by exposure to PAP; ▲: cells treated with NAC; ◇, cells pretreated with NAC followed by exposure to PAP. Statistical significance was determined from comparisons to time zero for ROS generation and vehicle-treated cells for GSH levels (*P < 0.05; **P < 0.01; ***P < 0.001; n ≥ 3).