3-Methylcholanthrene treated Rat

Analysis of transcriptional response changes in rats after treatment with 3-Methylcholanthrene Keywords: toxicity Rats were treated with 3-methylcholanthrene (MC) (100 umol/kg) in corn oil (CO) (2 ml/kg), or were given equal volumes of CO, i.p., once daily for 4 days. At 1, 15, and 28 day time points, the animals were sacrificed, and livers were stored at -800 C for later isolation of RNA. Gene expression was studied by cDNA microarray analyses. The analyses was conducted in the laboratory of Dr. Chris Bradfield of the University of Wisconsin. Gene expression was monitored using 4572 unique clones from liver-derived EST libraries fortified with clones of known liver genes representing ~4000 genes. These cDNAs represented toxicologically relevant genes such as drug metabolizing enzymes (e.g. P450s), inflammatory responsive genes (e.g. SAA-1), and genes that were previously identified as useful in classification of chemicals. All clones were then sequence verified from both 3’ and 5’ directions. Six replicates of each cDNA were printed on each array using a Microgrid II (Biorobotics, Woburn, MA). The labeled cDNA from both the MC-treated groups and from a pool of the corresponding controls were mixed and hybridized to the liver microarray for 18 h according to the Genisphere (Hatfield, PA) protocol, as described in EDGE, a scientific resource for toxicology-related gene expression information (University of Wisconsin, Madison)