Modifications to the in situ TUNEL method for detection of apoptosis in paraffin-embedded tissue sections

The in situ detection of cells undergoing apoptosis is increasingly important in the analysis of injury and degeneration in the central nervous system. Limited information is presently available on the quantification of apoptosis in paraffin-embedded brain tissue sections, a technique which would be most useful in the evaluation of archival tissue for diagnostic and experimental purposes. In this report, optimized conditions for tissue digestion and permeabilization using Proteinase K and Triton X and a quantification method for apoptosis detection are described using brain sections from aluminum maltolate-treated aged and young rabbits as compared to untreated matched controls. This method provides optimal staining of apoptotic cells without the problem of tissue destruction, and should prove useful in evaluating the process of apoptosis in neurodegenerative disorders.