(418u) Bioelectrical Impedance Measurements to Detect Changes in Tight Junction Expression at Cell Interfaces

Precisely determining barrier function of endothelial and epithelial cells to ion passage requires advanced electrical techniques. Impedance Spectroscopy, a non-invasive measurement system that can quantify the barrier integrity of a cell monolayer in real time, provides the best opportunity for doing so.We analyzed the effect of phenylarsine oxide (PAO)-induced proteolysis of occludins on Madin-Darby canine kidney (MDCK) cell monolayer impedance as a function of time using this method. Occludins are tight junctional proteins that have been shown to regulate the transport of ions, water and other molecules through cell monolayers. The cell monolayer is modeled as a parallel RC circuit, and the cell resistance and capacitance are recorded before and after the addition of the PAO containing media, providing information on the effect of occludin proteolysis to overall cell behavior. Impedance spectroscopy of the MDCK monolayers before and after treatment show a clear response of the cells both resistively and capacitively to the PAO containing media indicating that occludin proteolysis effects both the junctions and the cells. Further investigations are needed to determine how to modulate tight junction proteolysis in a manner that minimizes the effect on the cell capacitance and only affects the junctions.