Use of transepithelial electrical resistance in the study of pentachlorophenol toxicity

The toxicity of pentachlorophenol (PCP), a polluting substance believed to exert a narcotic effect, was assayed using the Caco-2 cell line as a model. In order to assess this toxicity as fully as possible, several viability t ests, each examining different endpoints, have been used. Neutral red uptak e was found to be more sensitive to PCP than MTT and Alamar Blue tests. Tra nsepithelial electrical resistance (TEER) was shown to be the most sensitiv e to PCP at concentrations and exposure times where the Alamar Blue, LDH le akage and Blue Dextran passage did not evidence any effect. Blue Dextran pa ssage and optical microscopy revealed cellular detachment at concentrations where LDH and Alamar Blue showed little or no cytotoxicity. Thus, PCP seem s to affect the integrity of the intestinal barrier at levels where no cyto toxicity is seen. Our results support the notion that TEER can be used as a very sensitive method for evaluating membrane-perturbing toxicants. (C) 19 99 Elsevier Science Ltd. All rights reserved.