title: In situ detection of fragmented DNA (TUNEL assay) fails to discriminate among apoptosis, necrosis, and autolytic cell death: a cautionary note.
abstract: Detection of DNA fragments in situ using the terminal deoxyribonucleotidyl transferase (TDT)-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay is increasingly applied to investigate active cell death (apoptosis). We studied the specificity of the assay in well-defined models of apoptosis and necrosis as well as in postmortem autolysis in rat liver. During involution of liver hyperplasia, which follows stopping treatment with the hepatomitogens cyproterone acetate (CPA) or nafenopin (NAF), numerous apoptotic hepatocytes could be observed with TUNEL-positive chromatin residues. A similar TUNEL-positive reaction appeared in necrotic hepatocytes after a cytotoxic dose of carbon tetrachloride (CCl4) or N-nitrosomorpholine (NNM). Also, in insufficiently fixed, autolytic livers TUNEL-positive nuclei were observed. Thus, DNA fragmentation is common to different kinds of cell death; its detection in situ should not be considered a specific marker of apoptosis.
authors.affiliation: Institut für Tumorbiologie-Krebsforschung der Universität Wien, Vienna, Austria.
authors.forename: B
authors.initials: B
authors.lastname: Grasl-Kraupp
authors.forename: B
authors.initials: B
authors.lastname: Ruttkay-Nedecky
authors.forename: H
authors.initials: H
authors.lastname: Koudelka
authors.forename: K
authors.initials: K
authors.lastname: Bukowska
authors.forename: W
authors.initials: W
authors.lastname: Bursch
authors.forename: R
authors.initials: R
authors.lastname: Schulte-Hermann
mesh_terms: D000818:Animals; D017209:Apoptosis; D001329:Autolysis; D002251:Carbon Tetrachloride / Q000494:pharmacology; D016923:Cell Death; D004247:DNA / Q000032:analysis*; D004249:DNA Damage; D005260:Female; D005821:Genetic Techniques; D008099:Liver / Q000166:cytology / Q000378:metabolism* / Q000502:physiology*; D008297:Male; D009336:Necrosis; D051381:Rats; D017208:Rats, Wistar
chemical_list: D004247:DNA; D002251:Carbon Tetrachloride