Junctional transfer in wounded cultures of bovine aortic endothelial cells

Both in vivo and in vitro, endothelial cells form continuous monolayers displaying growth control by cell density as well as cell contact. Several functions of endothelium are dependent upon maintenance of an intact monolayer. When such a monolayer is injured, endothelial cells migrate out from the wound edges and proliferate to cover the area of denudation. The response of endothelium to wounding is therefore a matter of both growth control and cellular motility. Since intercellular gap junctions have been postulated to have a role in growth control, we set out to determine whether junctional communication was altered in the activated, migrating cells. We found extensive transfer of microinjected fluorescent dye molecules (Lucifer yellow CH) in cells at or near the wound edge at various times after wounding (1 minute to 48 hours). However, cells near a wound edge transferred dye at a frequency significantly diminished from that observed in undisturbed monolayers (81.1 +/- 1.5 (SE) versus 92.7 +/- 0.8% of adjacent cells received dye). There was a significant positive correlation between transfer frequency and distance from the wound (expressed as intervening cells) but not between transfer frequency and time after wounding. These results suggest that endothelial cells in a wounded monolayer retain junctional communication at a slightly but significantly reduced level and that increased motility and the wound healing response do not necessarily correlate with total loss of communication.