title: A novel method to determine specificity and sensitivity of the TUNEL reaction in the quantitation of apoptosis.
abstract: Apoptosis is an important mode of cell death under both physiological and pathophysiological conditions. Numerous techniques are available for the study and quantitation of apoptosis in cell culture, but only few are useful when applied to complex tissues. Among these, the terminal transferase-mediated dUTP nick end-labeling (TUNEL) assay remains the most widely used technique. However, its specificity and sensitivity for the detection of apoptosis remain controversial. We developed a technique consisting of staining live cells and tissues with Hoechst 33342 and the vital dye propidium iodide (PI), followed by fixation and the TUNEL reaction. We demonstrate excellent retention of PI in necrotic cells after fixation. We also examined the distribution of TUNEL staining among necrotic and apoptotic cells in various models of cell injury in vitro and in vivo. We show that the sensitivity of the TUNEL varied between 61 and 90% in the models examined. The specificity exceeded 87% in all models but fell to 70% when a predominantly necrotic injury was induced. This novel and simple method will permit the determination of indices of sensitivity and specificity for the TUNEL assay in other tissues and experimental conditions.
authors.affiliation: Department of Medicine, Division of Nephrology, Indiana Center for Biological Microscopy, Indiana University, Indianapolis, Indiana 46202, USA.
authors.forename: K J
authors.initials: KJ
authors.lastname: Kelly
authors.forename: Ruben M
authors.initials: RM
authors.lastname: Sandoval
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Dunn
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Molitoris
authors.forename: Pierre C
authors.initials: PC
authors.lastname: Dagher
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis; D015687:Cell Hypoxia / Q000502:physiology; D002945:Cisplatin / Q000494:pharmacology; D004396:Coloring Agents; D005404:Fixatives / Q000494:pharmacology; D005557:Formaldehyde / Q000494:pharmacology; D020287:In Situ Nick-End Labeling / Q000592:standards*; D007511:Ischemia / Q000473:pathology / Q000503:physiopathology; D007668:Kidney / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D018374:LLC-PK1 Cells; D008297:Male; D009336:Necrosis; D011108:Polymers / Q000494:pharmacology; D011419:Propidium; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D012079:Renal Circulation; D012680:Sensitivity and Specificity; D013194:Staining and Labeling / Q000379:methods; D013552:Swine
chemical_list: D000970:Antineoplastic Agents; D004396:Coloring Agents; D005404:Fixatives; D011108:Polymers; D005557:Formaldehyde; D011419:Propidium; D002945:Cisplatin; C003043:paraform