Evom epithelial tissue volt ohmmeter

The integrity of the IPEC-J2 cell monolayer can be followed by measuring transepithelial electrical resistance (TEER) between the apical and basolateral compartments of the IPEC-J2 cells (Figure 2). Cells were seeded to 6-well Transwell insert containing plates (polyester, 0.4 μm pore size, Corning, Merck, Darmstadt, Germany), and the seeding density was 3 × 10⁶ cells/well. After the cells reached a confluent state, the barrier function was evaluated by measuring with an EVOM Epithelial Tissue Volt/Ohmmeter (World Precision Instruments, Berlin, Germany). 10 days after seeding, the IPEC-J2 monolayer achieved the 600 Ω/well values. The results were calculated as kΩ × cm² by multiplying the values by the surface area of the monolayer (4.67 cm²). The high TEER value of IPEC-J2 monolayers grown on Transwell polyester filters demonstrates the functional integrity of the continuous cell association, acting as a single-layer tight physical barrier.

IPEC-J2 cells were plated to confluence in 6-well polyester membrane inserts. The cells were washed threefold and incubated with 50 μM suramin and 200 ng/mL S1P for different time intervals (for 0.5, 2, 24, and 48 hr) in phenol red-free DMEM. TER measurements of cell layers were performed prior to and after administration of matriptase activators using EVOM Epithelial Tissue Volt/Ohmmeter (World Precision Instruments, Berlin, Germany). The average baseline electrical resistance of the polyester membrane insert without IPEC-J2 cell layer was 113 Ω, which was subtracted from actual TER results.

The nontransformed porcine intestinal epithelial cell line IPEC-J2, originally isolated from jejunal epithelia of a neonatal unsuckled piglet [17 (link)], was a kind gift of Dr. Jody Gookin, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA. IPEC-J2 cells were maintained on six-well Transwell polyester membrane inserts (Corning Inc., Corning, NY, USA) as it was described previously [18 (link)]. Transepithelial electrical resistance (TEER) measurement of monolayers was performed on alternate days after seeding, from day 5 to 21 of culture, using an EVOM Epithelial Tissue Volt/Ohmmeter (World Precision Instruments, Berlin, Germany).