title: Evaluation of putative biomarkers of nephrotoxicity after exposure to ochratoxin a in vivo and in vitro.
abstract: The kidney is one of the main targets of xenobiotic-induced toxicity, but early detection of renal damage is difficult. Recently, several novel biomarkers of nephrotoxicity have been identified by transcription profiling, including kidney injury molecule-1 (Kim-1), lipocalin-2, tissue inhibitor of metalloproteinases-1 (Timp-1), clusterin, osteopontin (OPN), and vimentin, and suggested as sensitive endpoints for acute kidney injury in vivo. However, it is not known if these cellular marker molecules may also be useful to predict chronic nephrotoxicity or to detect nephrotoxic effects in vitro. In this study, a panel of new biomarkers of renal toxicity was assessed via quantitative real-time PCR, immunohistochemistry, and immunoblotting in rats treated with the nephrotoxin ochratoxin A (OTA) for up to 90 days and in rat proximal tubule cells (NRK-52E) treated with OTA in vitro. Repeated administration of OTA to male F344/N rats for 14, 28, or 90 days resulted in a dose- and time-dependent increase in the expression of Kim-1, Timp-1, lipocalin-2, OPN, clusterin, and vimentin. Changes in gene expression were found to correlate with the progressive histopathological alterations and preceded effects on traditional clinical parameters indicative of impaired kidney function. Induction of Kim-1 messenger RNA expression was the earliest and most prominent response observed, supporting the use of this marker as sensitive indicator of chronic kidney injury. In contrast, no significant increase in the expression of putative marker genes and proteins were evident in NRK-52E cells after exposure to OTA for up to 48 h, suggesting that they may not be suitable endpoints for sensitive detection of nephrotoxic effects in vitro.
authors.affiliation: Department of Toxicology, University of Würzburg, Würzburg D-97078, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Rached
authors.forename: Dana
authors.initials: D
authors.lastname: Hoffmann
authors.forename: Kai
authors.initials: K
authors.lastname: Blumbach
authors.forename: Klaus
authors.initials: K
authors.lastname: Weber
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Dekant
authors.forename: Angela
authors.initials: A
authors.lastname: Mally
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D002273:Carcinogens / Q000633:toxicity*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005562:Formazans / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D007124:Immunoenzyme Techniques; D007674:Kidney Diseases / Q000139:chemically induced* / Q000473:pathology; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D009183:Mycotoxins; D019055:No-Observed-Adverse-Effect Level; D009793:Ochratoxins / Q000633:toxicity*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D015415:Biomarkers; D002273:Carcinogens; D015815:Cell Adhesion Molecules; D005562:Formazans; D008565:Membrane Proteins; D009183:Mycotoxins; D009793:Ochratoxins; D012333:RNA, Messenger; D013778:Tetrazolium Salts; C110936:Havcr1 protein, rat; C025589:ochratoxin A; C079782:MTT formazan