INVITRO CHROMOSOME ASSAY USING CULTURED RAT-LIVER CELLS

An in vitro chromosome assay was developed which utilizes an epithelial-like cell line derived from rat liver. The cell line, designated RL1, retains sufficient metabolic enzyme activity to detect chromosome damge induced by a variety of chemical mutagens and carcinogens without the incorporation of an extrinsic metabolizing system. The cells are grown on standard glass microscope slides, exposed to the test chemical and processed in situ for metaphase analysis. In a small validation study, chromosome damage was detected in cultures exposed to the direct-acting agents, methyl nitronitrosoguanine, 4-nitroquinoline-N-oxide, propylene oxide, epichlorohydrin and 1,2:3,4-diepoxybutane and to compounds requiring metabolic activation, including cyclophosphamide, 2-acetylaminofluorene, 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene. Negative results were obtained with pyrene and carbon tetrachloride.