Permanent embryonic germ cell lines of BALB/cJ mice - an in vitro alternative for in vivo germ cell mutagenicity tests

To offer a sensitive and predictive in vitro method to assess germ cell mut agenicity, we established primordial germ (PG) cell-derived permanent femal e and male embryonic germ (EG) cell lines of the mouse (strain BALB/cJ). Th e differences in developmental sensitivity of EG cells and differentiated f ibroblast cells of the mouse cell line 3T3 to genotoxicants were tested com paratively under identical test conditions. Cytotoxicity assay was measured by the MTT test and genotoxic effects were determined by sister chromatid exchanges (SCE) rates induced by standard reference mutagens. Both methods are used to assign the chemicals to two classes of in vivo reproductive tox icity, non- and strongly genotoxic to germ cells. Applying linear discrimin ant analysis, a biostatistical prediction model (PM) was developed for the female cell line EG(3). This procedure identified a single variable, the Ig (SCE(200)EG(3)) as the statistically significant concentration related incr ease of 200% in the mean number of SCEs per metaphase spread after 3 h of e xposure to be sufficient for separation into the classes: non- and strongly genotoxic to germ cells. Applying this PM to the training set of five geno toxic and three non-genotoxic test chemicals, 100% correct classifications were obtained. (C) 2001 Elsevier Science Ltd. All rights reserved.