The possible use for immunohistochemical detection of cells in S-phase labeled by bromodeoxyuridine.

Experiences with the use of bromodeoxyuridine (BrdU) as a marker of cellular division were described within this paper. BrdU is incorporated in the course of S-phase of cell cycle into the arising DNA in place of thymidine. The presence of BrdU in cell nuclei of tested tissues was detected with a monoclonal antibody and immunoperoxidase method. It was found that: 1. In adult rats a total dose of 100 mg is sufficient for labeling nuclei in most tissues, however intensity of the staining varies. The largest amount of BrdU was revealed in enterocyte nuclei. Lower level of BrdU was detected in cells in the spleen and in the interalveolar septa (probably macrophages) and the lowest one was found in the liver (hepatocytes, Kupffer, and Ito cells); with the exception of individual astrocytes no labeling was revealed in the central nervous system. 2. ED14 (14 days old) rat embryo that had been exposed to BrdU in the mother body, revealed only a weak labeling because of the uptake of BrdU in the placenta. The highest level of BrdU was observed in mesenchymal cells surrounding primitive organs. 3. Explants of the cerebral rat ED14 cortex that had been exposed to BrdU during intrauterine development, remain to be BrdU positive even after their transplantation into the recipient's brain. Different intensity of cell nuclei labeling reflects the rate of mitoses from embryonic day 12 (ED12) to ED14 when BrdU had been administered.