Flow cytometry and sorting of meiotic prophase cells of female rabbits

We present a new, flow cytometric method by which cells in various stages of the meiotic prophase can be quantitated and sorted in partly enriched fractions. Ovarian cells of 3-16-day-old rabbits were mechanically dispersed and fixed in ethanol and aldehydes. The cell suspension was stained with the DNA fluorochrome mithramycin and analysed and sorted in a FACS IV cell sorter according to the fluorescence and forward light scatter distribution. Cells sorted onto slides were stained with haematoxylin and eosin and differentially counted in the microscope. In the diploid fraction, preleptotene cells were more fluorescent than somatic cells. Leptotene cells were found throughout the S fraction and the tetraploid fraction. Zygotene and pachytene cells caused a major peak in the tetraploid region with 10-25% more fluorescence than somatic cells. Cells in diplotene had 5-15% more fluorescence than somatic cells. Mitotic cells were 20-40% more fluorescent than somatic cells and scattered the light more intensely than did meiotic cells with the same fluorescence.