In vitro germ cell models for the detection of fertility impairment

Pluripotent embryonic carcinoma cells and pluripotent embryonic stem cells established from undifferentiated cells of an early mouse embryo were inves tigated for induction of proliferation inhibition, sister chromatid exchang es (SCE) and single-strand breaks by treatment with various germ cell mutag ens. The comparison of malignant cells with nonmalignant cells showed an in creased sensitivity of nonmalignant cells independent of their state of dif ferentiation. Mitomycin C (MMC) inhibited the proliferation of nonmalignant cells at a concentration of 10(-6) M but did not affect growth of the tera tocarcinoma cell line P19. There were no differences between the investigat ed cell lines at a lower MMC concentration. At the concentration of 10(-6) MMC the sister chromatid exchanges of P19 were enhanced up to 41 SCE per me taphase. Testing of another germ cell mutagen, ethylnitrosourea (ENU), gave similar results: a decreasing generation time of nonmalignant cell lines a fter treatment with 1 mM ENU and no effect on the teratocarcinoma cells. Th is concentration also induced a high number of SCE. Single-strand breaks co uld be produced by exposure to methanmethylsulphonate (MMS). 56.3% of embry onic stem cell DNA was passing through the filter after MMS treatment. In c ontrast to the embryonic stem cells, only 35.6% of teratocarcinoma DNA was affected.