Cyclin D1 expression leads to ROS accumulation, which results in a DNA damage response and senescence induction. A) DCFDA assay in cultured pineal cells that are either wild-type (WT) or express Cyclin D1 (Cyclin D1). PC = phase contrast; OL = overlay. B) Immunofluorescence staining for the respective proteins in cultured Cyclin D1-expressing pineal cells (top panel), which have been treated with N-Acetyl Cysteine (NAC) or vehicle. The middle panel shows the respective DAPI-stained nuclei, and the lower panel shows the overlay (OL). C) Staining for senescence-associated beta galactosidase (SABG) in explanted Cyclin D1-expressing cells that have been treated with either NAC or vehicle, as indicated. D) Representative immunofluorescence staining for 4-hydroxynonenal (4HNE) in 10-day old Irbp-Cyclin D1 (D1) and wild-type (WT) pineal sections, as indicated. E) Representative immunostaining for the mitochondrial superoxide dismutase MnSOD in wild-type (WT) and Irbp-Cyclin D1 (D1) pineal sections, as indicated.