Quantitative Analysis of In Vivo Cell Proliferation

AbstractInjection and immunohistochemical detection of 5‐bromo‐2′‐deoxyuridine (BrdU) has become the standard method for studying the birth and survival of neurons, glia, and other cell types in the nervous system. BrdU, a thymidine analog, becomes stably incorporated into DNA during the S‐phase of mitosis. Because DNA containing BrdU can be specifically recognized by antibodies, this method allows dividing cells to be marked at any given time and then identified at time points from a few minutes to several years later. BrdU immunohistochemistry is suitable for cell counting to examine the regulation of cell proliferation and cell fate. It can be combined with labeling by other antibodies, allowing confocal analysis of cell phenotype or expression of other proteins. The potential for nonspecific labeling and toxicity are discussed. Although BrdU immunohistochemistry has almost completely replaced tritiated thymidine autoradiography for labeling dividing cells, this method and situations in which it is still useful are also described.