Flow cytometric analysis of the recruitment of G₀ cells in human epidermis in vivo following tape stripping

Tape stripping of human skin elicits a proliferative response of a synchronously-dividing group of cells. The progress of this cohort of cells has been monitored using two windows in the cell cycle, one located in mid-S phase and the other centred around G2 + M. The cellular DNA is measured with flow cytometry, the windows are defined by two ranges in the DNA histogram. The cohort can be described as the recruitment of cells from a pre-existing G0 compartment which consists of 76% of all proliferative cells. The duration of the S phase is calculated to be 10.2 hr and G2 + M phase 5.1 hr. The cell cycle time of 39 hr for normal human keratinocytes derived from these figures is in line with recent values obtained by different techniques.