Submitted to: Biochemica
Publication Type: Review Article
Publication Acceptance Date: January 1, 1998
Publication Date: N/A
Bromodeoxyuridine (BrdU), an analog of thymidine, is incorporated into DNA during the S-phase of the cell cycle, and is used to specifically label proliferating cells. This manuscript describes an improved technique for the detection of incorporated BrdU in fixed, paraffin embedded tissue sections with the use of microwave heat to denature cellular DNA, and to unmask incorporated BrdU for antibody detection. The effect of two common histological fixatives, and the use of microwave antigen retrieval were tested to determine the optimal conditions for BrdU detection in pulse labeled swine ovarian tissues. Carnoy's fixative is routinely used for tissue fixation following BrdU labeling, because detection of BrdU is more easily accomplished by conventional means employing HCl denaturation, than with stronger cross-linking fixatives such as formalin. Tissues fixed in buffered formalin, followed by microwave antigen retrieval produced more intense immunostaining for BrdU than tissues fixed in Carnoy's fixative. The use of formalin fixation is desirable because numerous other antigens can be detected in sections preserved with this fixative with the use of microwave antigen retrieval. The results of this basic research will be useful for scientists who wish to study the proliferation rate of cells and tissues in experimental animals, especially if they intend to study other antigens of interest in the same tissues. The use of BrdU to label proliferating cells eliminates the cost and hazard of disposing of animals that have been rendered radioactive by injection of tritiated thymidine.