Enhanced macromolecular permeability of aortic endothelial cells in association with mitosis.

Experiments were performed on thoracic aortae of 12 male Sprague-Dawley [corrected] rats to determine the statistical frequency of isolated leaks to Evans blue-albumin (EBA) conjugate at the level of individual cells and to assess the relationship of such leaks to the cell turnover process. Fluorescence microscopy was used to detect leakage of EBA around individual cells, and hematoxylin staining was used to identify cells in mitosis on the same specimens. Although endothelial cell mitosis is very rare in occurrence, 99% of the cells in the M phase were associated with EBA leakage. Since these dividing cells accounted for only one third of all cellular leakage sites, we concluded that significant leakage also occurred in other phases of the cell cycle, probably prior to and after the M phase, or during non-denuding desquamation.