Use of proteomic methods to identify serum biomarkers associated with rat liver toxicity or hypertrophy.
BACKGROUND
Our objectives were to identify serum marker proteins in rats that might serve as sensitive indicators of hepatomegaly, hepatocellular necrosis, or hepatobiliary injury and to use them to analyze data from a collaborative proteomics project.


METHODS
In each of 4 studies comprising the collaborative project, rats were given 1 of 4 compounds that target the liver through different mechanisms. Sera and liver samples were collected by terminal bleeds at 1 of 3 postdose time points. Sera were depleted of major secretory proteins and then separated into protein features by 2-dimensional gel electrophoresis (2DGE). Liver specimens were also processed and subjected to 2DGE. Protein spots that significantly increased or decreased in quantity after drug treatment were recovered, digested, analyzed by mass spectroscopy, and compared with available databases for identification. Criteria for further consideration were (a) temporal expression (i.e., increase or decrease at early, fulminant, or recovery periods), (b) known biological function, (c) probable hepatic origin, and (d) any previous association with toxicity in published studies. Markers that changed significantly at the early time point were important because of their potential sensitivity for signaling minimal damage.


RESULTS
Vitamin D-binding protein, paraoxonase, cellular retinol-binding protein, malate dehydrogenase, F-protein, and purine nucleoside phosphorylase were identified as empirically confirmed serum markers for hepatic effects in drug-treated rats.


CONCLUSIONS
Proteomics can be applied for the identification and confirmation of peripheral biomarkers for altered liver function after toxicant exposure.
Amacher
David E
DE
Molecular & Investigative Toxicology, World Wide Safety Sciences, Pfizer Inc., Groton, CT 06340, USA. david.e.amacher@pfizer.com
Adler
Rick
R
Herath
Athula
A
Townsend
R Reid
RR
D015058:1-Naphthylisothiocyanate; D000082:Acetaminophen / Q000633:toxicity; D000818:Animals; D015415:Biomarkers / Q000097:blood; D056486:Chemical and Drug Induced Liver Injury / Q000097:blood* / Q000473:pathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006984:Hypertrophy / Q000097:blood* / Q000139:chemically induced / Q000473:pathology; D008107:Liver Diseases / Q000097:blood* / Q000473:pathology; D008297:Male; D008747:Methylcellulose / Q000633:toxicity; D009929:Organ Size / Q000187:drug effects; D010634:Phenobarbital / Q000008:administration & dosage / Q000633:toxicity; D040901:Proteomics / Q000379:methods*; D011743:Pyrimidines / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley; D012680:Sensitivity and Specificity
D015415:Biomarkers; D011743:Pyrimidines; D000082:Acetaminophen; D015058:1-Naphthylisothiocyanate; C006253:pirinixic acid; D008747:Methylcellulose; D010634:Phenobarbital