Simplified differential staining of mouse sister chromatids

Many previously developed methods for sister chromatid exchange (SCE) analysis both in vivo and in vitro have been published during the past decade. Such methods have met with success in many but not all laboratories. These methods often involve expensive, hazardous equipment such as ultraviolet light and mercury lamps, as well as tedious treatments with hot salt solutions, acids or enzymes. The authors have developed an in vivo method using a 50 mg bromodeoxyuridine (BrdU) pellet combined with phosphate buffering at pH 6.8 and the use of a 300 watt, 130 volt inside-frosted incandescent bulb. Slides prepared from mouse bone marrow with this simplified method yielded many cells of excellent quality for SCE analysis, which were found to be highly reproducible.