Determination of Three-Dimensional Distribution of Apoptotic DNA Damage by Combination of TUNEL and Quick-Freezing and Deep-Etching Techniques

Apoptosis is a widespread phenomenon, which plays an important role in many physiological events as well as pathological processes (1 ). It was originally defined by its unique ultrastructural features, which were detected by electron microscopy (2 ,3 ). They are cytoplasmic shrinkage, nuclear chromatin condensation along nuclear margin, cell fragmentation into apoptotic bodies, and phagocytosis by adjacent epithelial cells or macrophages. It is also known that normal epithelial cell proliferation and death in mammalian prostatic glands depend upon an appropriate level of circulating androgen in blood (4 ,5 ). Therefore, the prostatic epithelial cells routinely undergo apoptosis by androgen withdrawal following castration in experimental male animals (6 ,7 ,8 ).