Bivariate flow cytometric analysis of murine intestinal epithelial cells for cytokinetic studies

The heterogeneous nature of the small intestine and the lack of methods to obtain pure crypt populations has, in the past, limited the application of standard flow cytometric analysis for cytokinetic studies of the proliferating crypts. We describe a flow cytometric technique to discriminate crypt and villus cells in an epithelial cell suspension on the basis of cell length, and to measure the DNA content of the discriminated subpopulations. Our data indicate that bivariate analysis of a mixed epithelial cell suspension can be used to distinguish mature villus cells, G1 crypt cells, and S-phase crypt cells. In addition, continuous labeling studies suggest that the position of a cell on the cell length axis reflects epithelial cell maturity. We applied this flow cytometric technique to determine the cytokinetic nature of epithelial cells obtained by sequential digestion of the small intestine.