Connexin Modulation in Rat Kidney Cells

NRK-52E cells, a cell line of rat kidney tubular epithelial cell origin, were obtained from American Type Culture Collection (Manassas, VA, USA) and cultured in DMEM/F-12 supplemented with 10% fetal bovine serum. Cells were grown at 37 °C in an atmosphere of 5% CO₂ in air^{48 (link)}, and then pretreated with connexin channel inhibitors heptanol, 2 mM, for 1 h (Sigma-Aldrich, a Cx43 uncoupler)^{49 (link)} or Gap26, 300 μM, for 1 h (Sigma-Aldrich, a connexin mimetic peptide)^{50 (link)}; a Cx43 expression enhancer, retinoic acid (RA), 10 μM, for 24 h (Sigma-Aldrich)^{4 (link)}; NAC (Sigma-Aldrich, a kind of ROS scavenger), 10 mM, for 1 h before H/R or/and LPS exposure. “Parachute” dye-coupling assay was performed as described below. The solvents of heptanol and RA were DMSO.