Figure 6: TUNEL Staining and Quantitation of Cellular Apoptosis

(A) Representative laminin, (B) DAPI, (C) TUNEL, and (D) a merged image of these 3 stains from a doxorubicin (DOX)-treated rat at 8 weeks following chemotherapy initiation. Yellow arrows point to nuclei costained with DAPI and TUNEL that were considered positive. (B) Quantified TUNEL-positive nuclei per 40× field (average over subendocardial and subepicardial fields for the lateral, septal, inferior, and lateral walls) between controls (n = 5) and DOX-treated rats (n = 5) at 4 weeks, and controls (n = 5) and DOX-treated rats (n = 4) 8 weeks following chemotherapy initiation. (E) ‡p < 0.05 within-group difference compared with 4-week rats. Values are expressed as median with interquartile range. TUNEL = terminal deoxynucleotidyl transferase-mediated nick-end labeling.