Figure 5

Induction of p-ERK1/2 in AR42J cells as indicated by immunohistochemistry. AR42J cells were grown and treated with 100 μM nicotine for 3 min; 20 μM H₂O₂ for 15 min. The cells were fixed with paraformaldehyde and treated with antibody to p-ERK1/2 for 1 h. After washing, the cells were treated with secondary antibody labeled FITC. Slides were observed using a confocal microscope A: Control untreated cells probed with primary antibody to p-ERK1/2 B: Cells exposed to nicotine for 3 min probed with primary antibody to p-ERK1/2 C: Cells exposed to H₂O₂ for 15 min probed with primary antibody to p-ERK1/2. Negative controls were done by incubating in FITC labeled secondary antibody only. (D – F). D: Control untreated cells. E: Cells exposed to nicotine for 3 min. F: Cells exposed to H₂O₂ for 15 min. The experiment was repeated in a set of four under each treatment.