Development of a toxicity test system using primary rat liver cells.

A model in vitro rat liver parenchymal cellular toxicity system employing cells obtained by the in situ collagenase perfusion technique has been developed to detect potential liver toxicants. The initial evaluation of this test system was accomplished using cadmium chloride, chromium chloride, cobalt chloride, mercuric chloride, nickelous chloride, sodium arsenite, sodium selenite, and ammonium vanadate. Linear regression analysis of the dose response curves was used to determine the effective concentration at which the viability was reduced to 50% (EC50). The relative toxicity of the compounds was as follows: Cd greater than V = As greater than Se greater than Hg greater than Cr = Co greater than Ni. Since several of the compounds with very similar EC50s had significantly different dose response slopes, an additional parameter, lowest effective concentration tested (LECT) was employed to assess the relative toxicity. The LECT was determined using the Williams test and the relative toxicity of the compounds was found to be Cd = Se greater than V greater than As = Hg greater than Co greater than Cr = Ni. The primary objective in developing this rat liver cellular toxicity test system was to employ an in vitro test system utilizing metabolically active primary cells from a potential target organ. This study demonstrates the utility of this test system in determining the relative liver cell toxicity of a series of inorganic agents of differing toxicity.