title: Improved sensitivity of the unscheduled DNA synthesis assay in primary rat hepatocytes following culture in serum-free defined media.
abstract: The unscheduled DNA synthesis (UDS) assay has been used extensively for the in vitro detection of DNA damage caused by compound exposure. However, the in vitro UDS assay has been insensitive for the detection of certain chemicals, particularly nitroaromatic compounds, that are positive in bacterial mutation assays. Recently, studies have been reported which describe alterations in the hepatocyte membrane following collagenase perfusion. Independently, a method for serum-free tissue culture has been developed which results in the up-regulation of cell surface receptors and which may restore membrane functions. Fourteen compounds, including seven nitroaromatics, were evaluated in the in vitro UDS assay employing a serum-free procedure. Five compounds that were previously reported positive in the standard in vitro UDS assay were also found positive using the serum-free method. In addition, five of the nitroaromatic compounds produced positive results with the serum-free method. 1-Methyl-3-nitro-1-nitrosoguanidine and 2-acetylaminofluorene, routinely used as positive controls in the UDS assay, showed greater activity in the serum-free assay. These results suggest that the use of serum-free media improves the sensitivity of the in vitro UDS assay and that the serum-free procedure potentially offers an effective alternative to the more labor intensive and more costly in vivo UDS assay.
authors.affiliation: Toxicology Research Laboratories, Lilly Research Laboratories, Greenfield, Indiana 46140, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Parton
authors.forename: D J
authors.initials: DJ
authors.lastname: Yount
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D004247:DNA / Q000096:biosynthesis*; D004249:DNA Damage / Q000235:genetics; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008297:Male; D009153:Mutagens / Q000633:toxicity*; D009154:Mutation / Q000187:drug effects* / Q000235:genetics; D009578:Nitrobenzenes / Q000633:toxicity; D051381:Rats; D011916:Rats, Inbred F344; D012015:Reference Standards; D013329:Structure-Activity Relationship
chemical_list: D016895:Culture Media, Serum-Free; D009153:Mutagens; D009578:Nitrobenzenes; D004247:DNA