Bromobenzene-induced hepatotoxicity at the transcriptome level.
Rats were exposed to three levels of bromobenzene, sampled at 6, 24, and 48 h, and liver gene expression profiles were determined to identify dose and time-related changes. Expression of many genes changed transiently, and dependent on the dose. Few changes were identified after 6 h, but many genes were differentially expressed after 24 h, while after 48 h, only the high dose elicited large effects. Differentially expressed genes were involved in drug metabolism (upregulated GSTs, mEH, NQO1, Mrps, downregulated CYPs, sulfotransferases), oxidative stress (induced HO-1, peroxiredoxin, ferritin), GSH depletion (induced GCS-l, GSTA, GSTM) the acute phase response, and in processes like cholesterol, fatty acid and protein metabolism, and intracellular signaling. Trancriptional regulation via the electrophile and sterol response elements seemed to mediate part of the response to bromobenzene. Recovery of the liver was suggested in response to BB by the altered expression of genes involved in protein synthesis and cytoskeleton rearrangement. Furthermore, after 48 h, rats in the mid dose group showed no toxicity, and gene expression patterns resembled the normal situation. For certain genes (e.g., CYP4A, metallothioneins), intraday variation in expression levels was found, regardless of the treatment. Selected cDNA microarray measurements were confirmed using the specific and sensitive branched DNA signal amplification assay.
Heijne
Wilbert H M
WH
Department of Biomolecular Sciences, TNO Nutrition and Food Research, PO box 360, 3700 AJ Zeist, The Netherlands. Heijne@voeding.TNO.nl
Slitt
Angela L
AL
van Bladeren
Peter J
PJ
Groten
John P
JP
Klaassen
Curtis D
CD
Stierum
Rob H
RH
van Ommen
Ben
B
D000818:Animals; D001969:Bromobenzenes / Q000633:toxicity*; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood / Q000209:etiology* / Q000473:pathology; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D005978:Glutathione / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D046228:Microarray Analysis; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects
D001969:Bromobenzenes; C032036:bromobenzene; D005978:Glutathione